Villager Housing

Give players the ability to invite villagers to stay at your place/village, either by paying them emeralds or by reaching an advancement. They'll stay if you give them a bed, a type of workbench, and a decent amount of space. You can choose which room the villager goes in with a banner they give you. Depending on the conditions of the living space, the villager will give you good or bad trades. Don't make the requirements too strict so players can open their minds to how they want to house their villagers, just as long as it's reasonable and not oppressive.