Minecraft wiki entry for Creating_custom_entity_add-ons, associated text: 1 Behavior Pack
1.1 Entities
1.2 Loot tables
1.3 Trading
1.4 Spawn Rules
2 Resource Pack
2.1 Entity
2.2 Animation Controllers
2.3 Animation
2.4 Models
2.5 Texts
2.6 Textures
2.7 Render Controllers
2.8 Sounds