I use this directory structure for hyper-casual and casual mobile game projects.
- Animations
- Audio
- Materials
- Models
- PhsyicMaterials
- Prefabs
- Resources
- Scenes
- Scripts
- Shaders
- Sprites
- Textures
- ThirdParty
- You must place editor scripts in a folder called Editor for them to work correctly. So Scripts/Editor is special folder that shouldn't changed.
- Unity lets you load assets in Resources folder via script. Resources also special folder that shouldn't changed.
- Keep naming rules consistent.
- Always use sub folders to save assets. Dont use the root. Create extra folder above if you really need special directory.