Minecraft wiki entry for Villager_trading_hall, associated text: 1 Purpose
2 Mechanics
2.1 Input
2.2 Storage
2.3 Output
3 Designs
3.1 Eggfur's simple trading hall
3.2 Eggfur's advanced trading hall
3.3 IanXO4's design
3.4 Mysticat's design
3.5 Tango Tek's design
3.6 sZPeddy's design
3.7 LogicalGeekBoy's Design (after village and Pillage update)
3.8 Standard design
4 Useful villagers
5 Decoration