Games where players are meant to come up with their own feats, abilities and spells
Hello everyone!
I am looking for games where there are no predetermined lists of spells, feats and abilities. Perhaps only a few ones as example and guidance.
I am looking for games where players are meant to invent their own spells, feats and abilities. Maybe even classes (or maybe the game is classless). I am looking for games that give you robust rules or guidelines to make this process possible and fun.
Something like "Pathfinder has rules to make your own spells!" does NOT work for me, because games with spell lists come with the implicit challenge of having to make spells that aren't redundant to the ones that already exist. I'm looking for true blank slates.
I also take suggestions of games where you don't have concrete spells and abilities but instead you negotiate this stuff during play. So long as there are rules/guidelines on doing so.
I would also like these games to have similar guidelines for gms: rules on how to make monster statblocks and balanced encounters, etc
Thanks in advance!