At 4th rogue level you can spend a rest dice as two bonus actions to grant advantage to your next attack this turn.
At 4th rogue level choose 2 upgrades:
Proper assassination - The rest rest dice cost of assassinate is refunded if your next attack reduces the target to 0 health.
Essence eater - If you slay a creature with your assassinate attack, you gain 1d8 arcane health.
Reflexes - You can spend a bonus action to grant yourself a +1 bonus to AC and dexterity saves until the start of your next turn.
Stalker - Attacking out of stealth deals an additional 1d6 damage. You gain a +1 bonus to stealth checks. You gain darkvision.
Lethal edge - Assassinate also causes the next attack to have its critical range increased by 1.
Versatility - Gain 2 extra cunning upgrades(rogue 3)
Bloodseeker - Whenever you deal piercing, force, or slashing damage, roll a 1d4<2 chance dice and inflict bleeding on the target on a success. Gain a +1 bonus to constitution.
At 5th rogue level, choose one of the following abilities:
Jittery nature - Swapping between weapons is a free action. Drawing a weapon is a free action. Your movement speed is increased by 5 feet. You have advantage on initiative checks. If you are the first character to act in the encounter, you have an extra action on the first turn.
Sadism - Increase the skewer, cruel, and regards weapon property damage dice by 1 size category. Treat the rend weapon property as being I tier higher.
Minor necromancy - Learn a necromancy cantrip. Use intelligence as the casting attribute. If it has only a somatic component, you can use dexterity as the casting attribute. Gain a +1d4 bonus to all checks made to investigate or examine corpses.
Dependency - After rolling a natural 1 on a save or skill check, you become afflicted, taking a -1 penalty to all d20 rolls until you take a long rest. This effect can stack, down to a -3. You procure 1d6+1 curative pills during a long rest, and can procure 1d2 pills at the cost of a rest dice during a short rest. Consuming the curative pill restores 1 fatigue, ends the affliction, and requires the consumer to make a DC 18 constitution save. On a success, they regain 1 rest dice.
The list - You have a list of characters, up to your charisma bonus + 1(min 1.) Your attacks gain a +1 bonus to hit and damage against targets on the list. You can gain advantage on a d20 roll associated with a target on the list once per target as a free action. You can place a creature on the list during a rest by spending a rest dice. A target is only removed from the list once slain, or by spending 4 rest dice during a rest. Killing a target restores 1d6 health.
Formality - If you deny yourself or your opponent a surprise round, you regain 2 rest dice at the start of combat.
Thorough - You have a +1d4 bonus to investigation, insight, or perception checks made to find or identify items and passageways. You gain a +1 bonus to all checks made to read and comprehend documents or texts. You can spend 2 rounds and 3 acid vials(or similar items) to completely remove a medium or smaller corpse and leave behind no recognizable remains.
Workaholism - Gain proficiency with a skill and tool of choice. Gain +1 bonus to checks made to do a job or long-term physical task.
Night person - Gain a +1 bonus to skill checks with skills you are proficient with during the night. You gain a temporary rest dice to use at dusk, which is lost at dawn if not used.
At 6th rogue level, when you kill an enemy, you can spend 1 rest dice to immediately gain another action.
At 6th rogue level, choose 2 upgrades:
Exerted Assasination - You can choose to take 1 point of damage to fatigue to use assassinate instead of spending a rest dice.
Combat training - Gain proficiency with two other weapon groups of your choice and increase the block DC of all your attacks by 2.
Greater sneak attack - Gain +1 sneak attack dice.
Arcane insight - Learn an arcane cantrip.