(these are subject to change as discussed by the group)

1. Intelligence Bonus: Characters gain an additional tool proficiency or language for each point of Intelligence bonus they have. Permanent intelligence increases grant additional bonuses, but temporary ones do not.Ability Score: Character statistics are not limited to 20, after creation.
2. Rule of Cool: If a player describes something difficult but cool they want their character to do, and it advances the story, it might succeed automatically. This can be done before or after attempting the check, if one is applicable.
3. Delay: In combat, you may choose the Delay action. You do nothing now but may re-enter the initiative order following any character or enemy action. Your initiative is reset to one less than the action you follow, and you are the first to act on the following initiative number.
4. Movement in Combat: If you leave a threatened space, and your total movement for the turn exceeds five feet, then leaving provokes an attack of opportunity.
5. Critical hit tables: On a critical hit, in addition to doubling the damage dice as usual, you will also roll on the critical hit tables for an additional effect. I have modified some Critical Hit tables I found, they are here
6. Fumble: If the d20 roll for an attack is 1, the attack is a fumble and leaves the attacker vulnerable. In addition, the attacker must roll on the fumble table for an additional effect.
7. Called Shots: A character may take disadvantage on any attack roll with a weapon or spell to aim at a specific area of the target’s body. A successful attack deals normal damage and inflicts a debilitating effect on the target until the beginning of the attacker’s next turn, or 1d4 rounds at the DM’s discretion. On a critical hit, the effect lasts until the end of the encounter, and may become a permanent injury at the DM’s discretion. The nature of the effect is DM’s discretion.
8. Multiple Attacks: At 7^th and 17^th level characters gain the Extra Attack class feature. If they already have this feature, the number of attacks granted increases by one. Spellcasters gain the new Extra Spell ability. This feature allows a caster to cast an additional spell when taking the Cast a Spell action. Each spell cast must have a casting time of 1 action or less.