Villagers interact with elements around them, and more with each other.

The villager should interact with the world around them, like the farmer currently does.
This would not be available for all villagers however, but I believe that all villagers should possibly be allowed to trade with each other, not as an often occurence though, if they get enough emeralds from trading with the player, or other villagers. This would only happen when a trade is locked in.

Armourer - Heal the iron golem?
Butcher - They could breed their animals, and maybe kill them? They are pacifists, so they may just breed the cows, say, with wheat they recieve from the farmer.
Cartographer - 
Cleric - Heal other villagers?
Farmer - (already implemented in game)
Fisherman - They should actually fish.
Fletcher - 
Leatherworker - 
Librarian - They could place books inside lecterns and chiselled bookshelves?
Stonemason - 
Shepherd - Shear sheep, and maybe breed them.
Toolsmith - Heal the Iron golem
Weaponsmith - Heal the Iron golem
Stuff left blank is what I didn't know what to do for.