Besides using monsters direct from folklore -- including ones rather different in your standard RPG -- two big ones are emerging for my works.
The simpler one is weapon proficiencies. Oh, there are rules that could let them wield what I want, but I'm just handing them the weapons and letting them fight.
The more complex one is raiding different spell lists to pull together a character's set. This is in fact necessary for some because I want thematic relationships, and -- the meager spell lists just don't let you build up a character's list without going for a grabbag approach.
Indeed, one character is getting a whole pile of homebrew spells because even adding some stuff metaphorically related to his theme leaves his list rather sparse.
