Minecraft wiki entry for Experience_farming, associated text: A variety of salable items can be produced by automatic farms, easily farmed by hand, or provided as surplus from a mob grinder. Note that if a villager has any options for their first tier of trades (Novice), you can effectively choose for them, if you have not actually traded with them yet: The trick is to break their job block and let them revert to unemployment, then replace the block. This does not work for higher-tier trades, but it does let you pick one book (often Mending) from a librarian, pick a farmer's first crop, and make sure that other professions do indeed offer their "cash machine" novice trades.