I want to add a Script every time a new Sprite is added to the Scene or created, because in our games Sprites should always have a script that controls textures and something else. How can I do this?
As I answered you here
you may create simple class with InitializeOnLoad attribute, in static constructor you should sucscribe to hierarchy update event:
EditorApplication.hierarchyWindowChanged += HierarchyUpdate;
and in HierarchyUpdate function - find and check all Sprites on the scene or something like this. Probably won’t be too complicated, but may occure some performance hit on large scenes