Materials from almost all officially published WotC material are available, though some have changes listed in these rules. All UA material, Stream content, and any features that are setting-specific require DM approval and possible modification before using.
In Primespace, one extra race is allowed from S:AiS/AAG:
The Autognome race, reflavored as a modern AI-piloted robot. You can choose to be Medium or Small. Upon death, Autognomes cannot be resurrected, but could theoretically be repaired or backed up.
(As a general rule, play Warforged if you want to RP a lifelike android with a soul, and play Autognome if you want to RP a soulless robot.)
Items not from official WotC material require heavy DM scutiny to be accepted, and may be reworked on the fly.
Currently accepted homebrew material for this setting specifically:
KibblesTasty Inventor
My current cyberpunk homebrew material
For your background, you may choose any two skill proficiencies and any two tool/weapon proficiencies or languages. Instead of two skill proficiencies, you may choose one skill expertise.
As this is a sci-fi/cyberpunk era campaign, background features have a lot of room to be reflavored and changed. Many jobs exist now that didn't exist in any normal D&D world, so if you want a completely different homebrew background, just tell the DM what profession you want your character to be trained in, and we can work out what your background feature could be, and what equipment you could start with.
When rolling stats, use 4d6 drop lowest 6 times, and reroll all 6 if the total is less than 70. If the total is over 70 but you still have no good stats, you can subtract 2 from one roll in exchange for adding 1 to another. You can do this up to twice, and you cannot increase a roll beyond 18 with this bonus.
When creating a low-level character, you start with the equipment provided in your class features and background in addition to the starting wealth listed for your class. When converting money between the PHB rules and the modern setting, 1sp = $1.
If you are creating a character at level 5 or higher, you get a different amount of money with which to purchase starting equipment, and get a certain number of free magic items. Use the following list instead of your class' starting wealth and equipment:
Level 5-8: $5,000 + 1d10×250, 1 common
Level 9-12: $25,000 + 1d10×1,250, 2 common, 1 uncommon
Level 13-16: $50,000 + 1d10×2,500, 3 common, 2 uncommon
Level 17-20: $200,000 + 1d10×10,000, 3 common, 2 uncommon, 1 rare
You can forgo getting two free magic items of one tier in order to start with one free magic item of a higher rarity tier. For example, you could give up two uncommon items to start with one rare item. This can stack with other free magic items; for example, at level 17 you could start with three common items and one very rare magic item.
You may spend starting wealth on whatever equipment you can afford before the first session. This potentially includes more magic items, but you cannot combine purchased magic items with your free magic items to get higher tier items.
Background Equipment: When choosing your class' starting gear, you can replace your weapons with anything from the Simple Weapons table. In addition, if you would normally start with armor, you can replace your starting armor with a Heavy Coat, Leather Jacket, Light Undercover Shirt, Concealable Vest, Light-duty Vest, or a Special Response Vest.
You can also swap out your adventuring gear for modern equivalents. For example, you could swap out a lantern for a flashlight.
In addition to normal starting equipment, you may also start with a smartphone or laptop.
Augmentations: I will allow you to take free cybernetic augmentations as part of character creation. Your free starting cyberware must have a point cost no higher than your character level. Any further cyberware must be purchased with starting cash.
You can also start with any amount of cosmetic bioware enhancements for free, but any bioware that has a practical purpose must be purchased.
Spells: If there is one specific spell that fits perfectly for your build, that isn't on your class' spell list, let me know, and I may allow you to take it as a class spell regardless.
Rules for reflavoring spell damage can be found in the Primespace Homebrew materials. Reflavoring spells on a purely aesthetic level is almost guaranteed to be allowed; all mechanical spell reflavorings need to go through me. Generally speaking however, I am much more lenient with reflavoring stuff in Primespace, due to how significantly different the setting is compared to most D&D settings.
S.I.N. and Permits: Unless your character is from the underdark or from another plane, your character probably has a System Identification Number, which allows governmental databases to track everything you do. You may choose to start with or without a valid SIN. If you start without one, keep in mind that you will need to buy a fake SIN in order to do certain things, like make purchases from public stores.
SINs also have legal permits attached. If you have a SIN for yourself or a Fake SIN, you may start with 1 free permit tied to your background. If it is your real SIN, you must meet the prerequisites for the permit or pay $200 per fake permit. Further permits can be purchased using starting wealth.
Karma: Variant Human is banned, though normal Humans get 1 extra skill, tool, or weapon proficiency.
If you want to start with a feat, you can take various flaws in order to get points to trade for them. Each flaw gives 1-3 karma. Half-feats cost 1 karma (without the +1), all other feats cost 2 karma. You can only choose up to three anti-feats, or up to 6 points worth of anti-feats. A list of Anti-feats can be found in the Primespace Homebrew materials.
If a creature is indefinitely incapacitated and there is no other threat around, any attack from within 5ft that would deal lethal damage to that creature automatically hits, and instantly reduces them to 0 HP.
On attack rolls, Critical Hits deal the normal damage for the attack, plus the maximum the dice could have rolled. For example, if a weapon attack would normally deal 2d6+4 damage, a critical hit would deal 2d6+4+12 damage. This applies to all dice rolled as part of the attack hitting - even if the target had the opportunity to make a saving throw to avoid half of it (e.g. poisons).
On saving throws, Critical Successes automatically succeed, and Critical Failures automatically fail.
On contested ability checks, Critical Successes automatically win, and Critical Failures automatically lose.
On regular ability checks, criticals mean nothing.
There are two new physical damage types: Ballistic and Friction
Ballistic damage is dealt by small items moving very quickly, such as bullets. It is similar to Piercing damage, but with items so small and fast that it would penetrate skin regardless of how sharp it is.
Friction damage is dealt by rubbing a creature along a relatively flat, rough surface. How much damage is dealt depends on how fast the creature/object is moving, and how rough the surface is. As a general rule to base other rulings off of, skidding along rough concrete deals 1d6 Friction damage x their speed (in MPH) divided by 10. For example, crashing at 50 MPH on a motorcycle deals 5d6 Friction damage.
Both of these damage types are considered nonmagical physical damage. If an ability or spell affects Bludgeoning, Piercing, and Slashing damage, then it also affects Ballistic and Friction damage.
Creatures at 0 HP and Unstable are not fully Unconscious. Instead, they are considered Prone and Stunned, meaning they are still somewhat aware of their surroundings and can speak falteringly. Creatures at 0 HP and Stable are Unconscious.
Any purposeful attack against a downed creature at 0 HP from within 5ft will inflict 3 failed death saving throws instantly if it hits.
Failed death saving throws last until a creature's next long rest. A creature can expend hit dice over a short rest to remove failed death saving throws (one die per saving throw). Hit dice expended to remove a death saving throw restore no hit points.
Each time a creature drops to 0 HP, they gain a level of Exhaustion. This rule does not apply to Path of the Zealot Barbarians.
If you have proficiency in an Artisan's Tool, You can spend downtime to craft a nonmagical object with that tool. You must have raw materials equal to half the value of what you want to craft. If what you are trying to craft costs $100 or less, you can complete it in one 8-hour workday. Otherwise, each day you work on it you can make $100 worth of progress, and the item is completed when you have spent enough time on it to match its price. If you have Expertise in the necessary tool, you can craft $200 worth of stuff per day.
Enchanting magic items has its own system, detailed in the Primespace Homebrew materials.
You can use downtime to gain abilities beyond those listed in your class. You must have some roleplay reason to want the abilities, a roleplay justification for how you're learning, and must describe at least partially what you are doing during downtime to train. Each downtime day requires approximately 8 hours of training, and gives a number of Downtime Points equal to your Intelligence score. If you are training directly under someone who has the skill you are learning, you may add their proficiency bonus to your daily Downtime Points.
You cannot train yourself from nothing. In order to learn a new skill or ability, you either need to find reference material or a teacher. Either way, it could end up being an expensive or involved process, depending on how you go about learning.
See the below list for how many points are required to gain a downtime ability, what prerequisites each ability has, as well as the amount of time it'll take to learn if you're training alone and you aren't below average Int.
Downtime Ability Training Time
Simple Weapon Proficiency: 60 points (3-6 days)
Martial Weapon Proficiency: 180 points (9-18 days)
Tool Proficiency: 300 points (15-30 days)
Language: 450 points (23-45 days)
Skill Proficiency: 600 points (30-60 days)
Skill/Tool Expertise: 900 points (45-90 days), requires proficiency
Armor Proficiency: 900 points (45-90 days), requires proficiency in previous tier
Half-Feat: 900 points (45-90 days), requires any prerequisites for the feat, and you don't get the +1
+1 to an Ability Score: 900 (45-90 days), up to a maximum of 20
Feat: 1800 points (90-180 days), you need any prerequisites for the feat
You may also train yourself to get another class or subclass feature, if that feature is gained from study and practice - not from a specific source of power. You must be at least double the level at which that feature is normally obtained, and meet all multiclassing prerequisites for that class. Learning the ability requires a number of downtime points equal to 200 × (the level at which that feature is obtained). For example: in order to learn Uncanny Dodge, you must be level 10+, have 13+ Dex, find a level 5+ Rogue willing to train you, and invest 1000 downtime points into training it.
Some creatures may have 2 separate creature types, determined on a case-by-case basis by the DM. As such, they are affected by anything that affects either of their creature types. However, if one of their creature types is immune to an effect but the other isn't, the effect is reduced in a way determined by the DM.
Planetouched races such as Tieflings and Aasimar (including Warforged, for balance reasons) are considered Humanoid, but with non-humanoid influence that is divinable by certain spells and magical effects, and may affect how they react to certain abjuration magic. Undead creatures will never retain any semblance of their previous creature type, apart from appearance.
EXP is awarded primarily for successfully pulling off missions/goals, but is also awarded in smaller amounts for surviving or bypassing combat encounters, discovering secrets, and navigating social encounters.
An Arcana check may reveal whether an item has magical properties or not, and sometimes the nature of the enchantment if the effects are readily apparent. Focusing on an item over a short rest does not reveal the nature of the item unless you attune to it.
If you wish to craft, repair, or manipulate something without tools specifically made for the job, you can attempt to do so with whatever you have access to, provided you can justify how you want it to work. For example, you could make an improvised set of Thieves' Tools with bent wire, or an improvised set of Hacking Tools with scripts quickly downloaded off the internet.
When you make a check using improvised tools, you have disadvantage on the roll.
Every creature's base initiative bonus is their Dexterity modifier plus their Wisdom modifier.
Spending inspiration allows you to treat one ability check, attack roll, or saving throw as if you had rolled a natural 20, though this does not count as a critical success. You cannot choose to do this if you have already rolled.
When damage would reduce you to 0 HP but not kill you outright, you can use a reaction to expend and roll one hit die, regaining hit points equal to what you rolled plus your Constitution modifier. When you do so, you gain a point of Exhaustion, and you must make a Constitution saving throw against a DC equal to the damage that put you to 0. On a failure, you gain a Lingering Injury.
Each damage type has a different Lingering Injury table. For these tables, see the Primespace Homebrew materials.
Whenever two spellcasters are in a 1v1 battle with no other threats, they enter a Mage Duel. This acts mostly the same as a normal round of combat, but with the following additional rules:
Every spell with a casting time of 1 Action or lower can be used as if it were Counterspell, if you can justify how the spell's effect nullifies the effect of your opponent's spell. For example, you could cast Wall of Fire to shield yourself from a Cone of Cold.
When casting a spell in this way, its casting time becomes one Reaction, and its duration becomes Instantaneous.
Like Counterspell, countering in this way automatically works if the spell's level is greater than or equal to the level of the countered spell.
Unlike Counterspell, if the countering spell was lower level, the two spellcasters make a contested check using their spellcasting ability to resolve the conflict. If the lower level spell is a Cantrip, the person casting it has disadvantage on this check.
If you have the Arcane Duelist feat, it applies to every spell you cast in this way.
Some organized dueling rings have optional rules layered on top of these, to make fights more interesting or more survivable. Not all of these apply at every dueling ring, but these are the most common extra rules:
The fight ends before either side reaches 0HP: some dueling rings stop when one side is Bloodied, while other, lower-level rings might only go to first blood.
Necrotic damage is banned (and sometimes lethal damage entirely).
Spells only - no other weapons or attacks.
If both sides run out of spell slots/spell points, the duel is a draw.
Counterspell and Dispel Magic are banned (come on, be more creative).
The Modern Magic UA lists a number of spells fitting for a modern setting. These spells are on the following class spell lists:
On/Off: Artificer, Bard, Sorcerer, Warlock, Wizard
Infallible Relay: Artificer, Bard, Sorcerer, Warlock
Remote Access: Artificer, Sorcerer, Warlock, Wizard
Arcane Hacking: Artificer, Wizard
Digital Phantom: Artificer, Bard, Warlock, Wizard
Find Vehicle: Artificer, Paladin
Haywire: Artificer, Warlock, Wizard
Invisibility to Cameras: Artificer, Bard, Sorcerer, Warlock, Wizard
Protection from Ballistics: Cleric, Paladin, Ranger, Wizard
Conjure Knowbot: Artificer, Wizard
Synchronicity: Bard, Cleric, Sorcerer
System Backdoor: Artificer, Wizard
Commune with City: Cleric, Ranger
Shutdown: Artificer, Sorcerer, Warlock, Wizard
Range does not affect lethality. Psychic and Lightning damage can be made nonlethal without issue; targets will drop to 0 and be stable. Bludgeoning damage can be made nonlethal if it is the result of an attack roll, and targets will drop to 0 and be stable. Necrotic damage cannot be specified to be nonlethal.
All other types of damage can be made nonlethal if the damage was dealt as the result of an attack roll. If such an attack reduces the target to 0 HP, the creature becomes Unstable, making death saving throws according to player rules.
Player Characters at 0 HP will follow RAW for the most part, with one exception - if a PC takes nonlethal Bludgeoning, Lightning, or Psychic damage and they drop to 0, the character will be immediately stable.
All spells which can supposedly affect anything on the same plane as you, but cannot target anything on different planes (e.g. Teleport, Dream), can instead only affect targets on the same 'layer' of whatever plane you are on. Each plane has a different definition of 'layer':
On the Prime Material, this refers to individual planets.
The Feywild and Shadowfell have different individual planets as well, mirroring the Prime Material's
Under the Great Wheel cosmology, The Elemental Planes were once part of one large plane called the Elemental Torus, with nigh uninhabitable border regions between the quadrants. Now, in the World Tree, each one is a separate plane, each with 1 layer.
The Ethereal Depths is its own 'layer', as is every instance of the Border Ethereal
The Astral Sea has no innate layers, but artificial "layers" have been magically created (e.g. Bags of Holding and the Demiplane spell)
The Outer Planes each have their own unique and weird structures (results may vary)
The Gate spell can still connect to whichever layer you want, so long as your destination is not magically warded from planar travel. Plane Shift can only take you to the first or 'primary' layer of that plane (e.g. you can plane shift to Avernus, but not Dis).
Spells can be prepared at the end of a long rest or during a short rest. This process takes 1 minute per spell level per spell (both the spells you're preparing and un-preparing), and requires concentration and the ability to perform verbal and somatic components for the duration. If a spell requires material components or a focus, it cannot be prepared without the material components or focus present.
After being resurrected via Revivify, Raise Dead, or similar magic, you permanently have one failed death save. After being resurrected twice, you have two permanently failed death saves. After being resurrected for a third time, the next time you would normally be at 0 HP and unstable, you die instantly and cannot be revived. This restriction does not apply to Zealot Barbarians, the Reincarnate spell, or Undead.
Every character gets a bonus to their speed equal to 5 times their Strength modifier or Dexterity modifier, whichever's lowest. If one of those ability modifiers is negative, then the speed bonus is 0. If both ability modifiers are negative, your speed is reduced by 5x the smaller penalty (whichever bonus is closer to 0).
There are 3 known types of magic in the world that can be inscribed in a spell scroll: Arcane, Divine, and Natural. If you can cast at least one spell of first level or higher, you can use any spell scroll of the same type of magic. Which type of caster you are depends on how you got your magic. There are rarer types of magic as well, but those generally cannot be inscribed as scrolls.
If you have proficiency in Arcana, you can use Arcane spell scrolls even if you do not know any Arcane spells. The same applies to Religion for Divine scrolls and Nature for Natural scrolls. If you do not know any spells of the relevant casting type, or if you do not have a spell slot high enough to cast the scribed spell, you must make an Arcana, Religion, or Nature check to use the scroll.
If you cast more than one spell on your turn, their combined level must not add up to more than the highest level spell you are able to cast or the highest level spell slot you have (whichever's higher). Cantrips count as level 0.
The magic tattoos from Tasha's Cauldron are available, but are not flavored as described in the items' descriptions. Instead, they are created using tattoo ink infused with residuum, and effectively must be applied by a tattoo artist casting Enchant Magic Item using a specialized tattoo needle that is itself enchanted to handle the residuum. Unattuning from a tattoo does not result in the tattoo disappearing, but does result in being unable to use the tattoo's magical properties, and the tattoo will fade to be almost invisible. The tattoo will also temporarily fade inside an Antimagic Field.
Spellwrought tattoos can be created without casting Enchant Magic Item, but do disappear completely once used. Applying one requires a skill check, similar to crafting an expendable magic item.
Tattoos can only be applied to skin. Depending on race and cybernetic augmentations, this may limit the number and location of potential tattoos.
When starting a vehicle from a full stop, it cannot move further than its Combat speed that turn. After the first turn, it can accelerate up to its top speed. If a vehicle is traveling in a straight line, or making a 45 degree or less turn, it can be going any speed up to its top speed, chosen by the driver when they use their Action to control the vehicle. In order to be able to make tighter turns, the vehicle cannot go above its Combat speed. Some vehicles that are hard to turn may not have a combat speed, in which case it can never turn more than 45 degrees in one round.
If the vehicle is in manual control mode, one creature must use an Action every round to drive the vehicle. When doing so, the driver decides what speed the vehicle is going, and moves the vehicle. If an entire round passes with nobody driving, the vehicle swerves and may crash. The driver may need to make an ability check each round to control the car in heavy traffic or other adverse conditions, with a DC depending on their speed and the obstacles.
If the vehicle is in autopilot mode, the AI will act on initiative count 20, obeying all traffic laws and driving as safely as possible. If the autopilot has been hacked, then what happens depends on what the hacker attempts to make the vehicle do. A hacker may decide to give the vehicle false information or change its destination, in which case the AI would still act on initiative count 20. Alternatively, a hacker could take complete control of the vehicle, in which case the hacker would be considered equivalent to a manual driver.
If a vehicle in motion hits an obstacle, whether that obstacle is a creature, another vehicle, or some other object, both the obstacle and the vehicle take bludgeoning damage from the impact equal to the fall damage that the vehicle would take from falling a number of feet equal to their current speed in mph. If the obstacle is not reduced to 0 HP from this impact, the vehicle crashes and stops moving. If the obstacle is a creature or another vehicle that is being controlled, that target can potentially dodge the crash. If the impact was on purpose, the driver/pilot must make an attack roll using the vehicle's Dexterity. Otherwise, the target must make a Dex save, against a DC equal to 10 + (the vehicle's speed in mph)/10. On a missed attack, or on a successful save, the vehicle does not impact the target.
If a Huge or smaller vehicle takes bludgeoning or thunder damage, whether that damage is the result of a crash or not, half that damage is also dealt to all creatures in the vehicle. If a Gargantuan or Colossal vehicle takes damage, what happens to the passengers depends on their positioning within the vehicle and where the damage happened. This damage can be further reduced by safety devices such as airbags and seat belts.
If a vehicle has the Open property and no seat belts, harnesses, or similar mechanism, crashes will fling the passengers from the vehicle instead of transferring the damage. The amount of damage the passengers then take is decided by the DM depending on where they were flung and how fast.
All abilities which normally last for or recharge after 7 days have that duration shortened to 6 days.
Druid:
Wild Shape (lv2): While transformed, you count as dual type Humanoid/Beast.
Elemental Wild Shape (lv10 Moon): While transformed, you count as dual type Humanoid/Elemental.
Inventor (KibblesTasty):
Stormforged Weapon (lv1 Cannonsmith): You can replace the base stats of your starting Stormforged Weapon with the stats of any Simple modern weapon. You can also turn any modern nonmagical weapon into a Stormforged Weapon, expending $2000 worth of raw materials over 3 downtime days to do so.
Rogue:
Sneak Attack (lv1): Damage dice increase in size when you reach certain levels in the Rogue class: d8s at 5th level, d10s at 11th level, and d12s at 17th level.
Identify: Can identify cursed items if and only if the cursed item was enchanted with an equal or lower spell level than the one used to cast Identify. Ritual casting Identify makes it count as 1st level.
Mage Armor: The target's base AC becomes 10 + your spellcasting ability modifier + its Dexterity modifier.
Barkskin: AC increased to 17; does not require concentration.
Dispel Magic: Can only dispel one spell per cast. You must specify what spell you are dispelling (you do not necessarily need to know exactly what the spell is, only that it's there). Also may be able to dispel other magical effects or properties, with a DC dependent on DM judgement.
Sending: Modern magitech can intercept Sending messages, like unencrypted radio signals.
Summon Lesser/Greater Demon: These spells are banned. Not for balance reasons - the Abyss just happened to get thrown into a black hole.
Stoneskin: Grants resistance to non-siege physical damage (bludgeoning/piercing/slashing/ballistic/friction), and grants 5 points of damage reduction for all types of damage except for Force, Psychic, and Poison.
Plane Shift: Plane Shift can only take you to a location on the plane's first or primary layer/planet. For the Material Plane, this is the planet Prima.