Glory to the Guildless
XP for 1s and 20s
One of my favourite variants – it adds a lot of fun:
When a player rolls a natural 1 or a natural 20, they get an amount of XP equal to their level x 5 (so 20XP at level 4).
The idea is that when a character stuffs up badly, they learn from their mistake, and when they push themselves to the limits of their ability, they grow the ability.
It also softens the the blow of a natural 1, and heightens the celebration of a natural 20!
(also encourages extra role-playing skill rolls as there’s always a chance of XP)