Hey, you're welcome!

You mean for design files like .sketch, .ai, etc?

For these, there used to be LayerVault (shut down) and Pixelapse (shut down after it was acquired by Dropbox).

http://gemba.io is a git client that aims to make versioning static files easier, although it's not exactly what you're looking for.

Plant App is the most promising thing, currently, but it's still in closed beta: https://plantapp.io/

Hope this helps! ☺️