Minecraft wiki entry for Wither_skeleton_farming, associated text: 1 Preparation
2 Creation
2.1 Building the mob collectors
2.2 Grinding Point
2.3 Vwoop's Design
2.4 Mikecraft’s Design
2.5 Kkinders Method
2.6 Other Addons
3 Automatic and AFK-able designs
3.1 Xisumavoid's Design
3.2 Ray's Works's Design
3.3 Ray's Works's Design (Video tutorial by Shulkercraft)
4 Bedrock edition farms