Assets defined in C# and created through tools. You can define your own <a href="https://wiki.facepunch.com/sbox/Custom_Asset_Types">Custom Asset Types</a>.
Clothing, DecalDefinition, Sandbox.ResourceExtension<T>, PrefabFile, SceneFile, Soundscape, SoundEvent, Surface, TerrainMaterial, TerrainStorage, VoxResource, ActionGraphResource