Genre Books for D&D Next:
These are all 100% compatible with fantasy D&D Next rules and settings. A high fantasy D&D character could hop worlds and multiclass in Modern and Future classes: Fighter 3/Gunslinger 3/Starpilot 3.
The Genre Books series covers all:
The d20 Modern, d20 Future, and d20 Past campaign models
The d20 mini-games from Polyhedron magazine
The Alternity campaign settings
The Amazing Engine campaign settings.
The settings of the non-medieval TSR mini-games
The other TSR/WotC rpgs, such as Boot Hill and Top Secret
Plus Campaign Models from existing D&D Worlds, showing how these Genres can be played in a Fantasy campaign.
Whereas the Culture Books cover the Ancient, Medieval, Renaissance, and pre-Industrial Enlightenment cultures, along with the "timeless" Indigenous cultures, the Genre Books cover post-Enlightenment fictional genres, from the French Revolution and Industrial Revolution, onward.
D&D Modern
Campaign Models:
Urban Arcana (the default timeline of D&D Earth)
Dark•Matter
Shadow Chasers
Agents of PSI
Genetech
Magitech setting from Amazing Engine.
Greyhawk 2000
Besides Greyhawk 2000, modern versions of all published D&D Worlds, with technology and cultural level equivalent to present-day 2012. For those Worlds which feature Real World correlations, keep it straightforward (e.g. Shou Lung = China) so that it's easy to use D&D Earth adventures and resources (e.g. culture books).
"Modern Realms": something like: Faerunian Union, United Realms of Anchorome (URA), People's Republic of Shou Lung, etc.
"Modern Eberron"
"Modern Athas"
"Modern Aebrynis"
"Modern Mystara". something like: The Known Union, the United Coast of the Southold (UCS).
"Modern Krynn"
"Modern Nerath"
D&D Pulp
Campaign Models:
Pulp Heroes d20 mini-game, later a campaign model for d20 Past
The Seedy Streets of Northport, setting for Pulp Heroes in Polyhedron Magazine
Iron Lords of Jupiter from Polyhedron
Shadow Stalkers from d20 Past
Masque of the Red Death
V is for Victory from d20 Modern
For Faerie, Queen, and Country from Amazing Engine
Gangbusters
Dawn Patrol (there was D&D/Dawn Patrol crossover in Frank Mentzer's AC4: The Book of Marvellous Magic)
Eberron campaign models, for using Pulp themes in a medieval fantasy setting
Better than Thrilling Tales. Maybe collaborate with GM Skarka.
D&D Supers
Campaign Models (the Supers timeline of D&D Earth is fictional within the Urban Arcana timeline. The Supers campaign models are comic book stories within the Urban Arcana campaign model):
Golden Age supers in D&D Earth
Silver Age supers in D&D Earth
Bronze Age supers in D&D Earth
Modern Age supers in D&D Earth
Red Curse of Mystara (Red Steel/Savage Coast) designed as superpowers
Better than MnM. A tough act to follow. Maybe collaborate with Steven Kenson.
D&D Anime
Campaign Models for all the different anime subgenres
Better than BESM
D&D Mecha
Campaign Models:
Mecha Crusade from d20 Future
Earthshakers from Mystara
Better than Battletech and d20 Mecha by Guardians of Order
D&D Western
Campaign Models:
Boot Hill
Cimarron County in Mystara (Red Steel/Savage Coast)
Remember the Alamo from the TSR mini-game
5e stats for Murlynd
Better than Sidewinder, Deadlands, and Aces & Eights
D&D Pirates
Also serves as "Caribbean Adventures" culture book for Afro-Caribbean, Taino, and Carib Indian cultures.
Campaign Models:
Pirates of the Sea of Fallen Stars in Toril
Merry Pirates of the Hollow World
Nuari of the Pearl Islands of Mystara (Afro-Caribbeans)
Caymen (Carib Indians) from AC2: Combat Shield and Mini-Adventure
Better than Skull & Bones, Buccaneers & Bokor d20 magazine, and 7th Sea: Swashbuckling Adventures
D&D Spies
Campaign Models:
Top Secret
Glantrian Diplomatic Corps from Mystara
Better than Spycraft
D&D Comedy
Compile the silliest D&D monsters, magic items, spells, and so forth.
The little-known Goldshitter from a Basic D&D Hebrew-language adventure module, might be the most silly monster in all the D&D Worlds.
Stats for the Dread Gazebo.
Resources:
"The Stupidest D&D Monsters" website and the April Fools Dragon magazine issues.
AC11, The Book of Wondrous Inventions with D&D versions of boomboxes, vending machines, etc.
1e Jester NPC class and its support articles in Dragon magazine
2e Jester kit for the Bard.
Includes a new 5e Jester class or theme
Also comedic settings for D&D Modern/Future/Past campaigns.
Campaign Models:
Hi-Jinx from d20 Modern
Thunderball Rally from d20 Modern
Tabloid! from Amazing Engine
They've Invaded Pleasantville and Icebergs TSR mini-games. The funny thing about Icebergs is that TSR made such a weird little game.
Mystara's Kingdom of Ierendi as portrayed as the Magnum P.I. television show, and the Broken Lands as portrayed in GAZ10: Orcs of Thar and the OrcWars! game
The Whamite Isles in the Forgotten Realms from The Great Khan Game.
The alternate "joke-version" of Castle Greyhawk from WG7 . This is an alternate timeline of Oerth--"Joerth"?
Campaign Models for the comics featured in Dragon Magazine over the years: Wormy, SnarfQuest, Yamara, Knights of the Dinner Table, Nodwick, Dork Tower, and The Order of the Stick
Include Campaign Models for all the Aldrazar settings which are based on WotC IP: GreyHack, HackJammer, HackWurld of Mystaros, Robinloft, and the Fading Realms
Better than HackMaster Basic, Paranoia, Tales from the Floating Vagabond "ludicrous sci-fi" rpg, Green Ronin's Damnation Decade, and SJG's Toon and Munchkin rpgs
D&D Sci-Fi
Campaign Models:
Star Frontiers (also encompassing Star Law campaign model from d20 Future)
Star*Drive
Bughunters from Amazing Engine and d20 Future
From the Dark Heart of Space from d20 Future
The Galactos Barrier from Amazing Engine
Once and Future King from Amazing Engine
Revolt on Antares from Tom Moldvay's TSR mini-game
Attack Force TSR mini-game. Novaship and Arcturus
Home setting of the spaceship from Expedition to the Barrier Peaks
Galactic Federation from Mystara (essentially D&D Star Trek)
Better than Traveller
D&D Cyberscape
Campaign Models:
CyberRave from d20 Cyberscape
Deathnet d20 mini-game
Kromosome from Amazing Engine (?)
D&D Apocalypse
Campaign Models:
Gamma World (including Omega World)
The Wasteland from d20 Future
Atomic Sunrise from d20 Apocalypse
Earth Inherited from d20 Apocalypse
Plague World from d20 Apocalypse
Campaign Models set in the aftermath of the historic apocalypses of the D&D Worlds:
The Rain of Colorless Fire from Greyhawk
The Great Rain of Fire from Mystara and Blackmoor
The Cataclysm from Dragonlance
The Apocalypse Stone from AD&D 2e
Better than Darwin's World.
D&D Timetravel
Supports not only timetravel, but all dimension-hopping inter-genre campaigns
Classes: Chronomancer, Temporal Champion, Temporal Raider, Dimensional Ranger
Resource: "Chronomancy and the Multiverse" by Roger Moore. Describes how time-travel applies to each D&D World.
Campaign Models:
Mystara: The Nexus from CM6: Where Chaos Reigns ; perhaps an Oard PC race, à la Star Trek's "I, Borg" episode.
Tales from the Comeback Inn, bringing Blackmoor to any campaign
The River of Time: time-travel in Krynn
Dimension X from d20 Future
Tangents from Alternity
Others:
Perhaps D&D Gaslamp (Victorian and Edwardian fantasy, which would include Masque of the Red Death, Shadow Stalkers, and For Faerie, Queen, and Country; otherwise include in D&D Pulp)
Perhaps D&D Steampunk
D&D Storybook, which would feature rules modules which support genres of fantasy which are more story-oriented, with little to no combat. The classes would be "story roles" instead of "combat roles". But they'd still be mechanically compatible with core D&D. D&D Storybook would feature campaign models which tell stories like Narnia, Wizard of Oz, Jim Henson's Labyrinth and Dark Crystal, and The Neverending Story. These might even be "D&D Earth" versions of some of those copyrighted worlds--for example, a quasi-Narnian campaign setting written by a "D&D Earth version" of C.S. Lewis who exists in the Urban Arcana timeline. In Urban Arcana, these are novels. Alice's Wonderland, as seen in EX1: Dungeonland and EX2: The Land Beyond the Magic Mirror, could be a campaign model.