Basically just what the title says. I figured out I can give regions to NPC opponents, but wish I could do that for free cities and vassals as well.
#Gift Province to Free City, Vassals
urban quest
pallid zodiac
Being able to gift ancient wonders to vassals that have them in range, and being able to "buy" provnices off them with imperium in order to annex important chokepoints on the map or (importantly) spirit dens would be huge.