Usually we use email, FTP, Google Drive to collaborate and share CAD data with other people
In the field of version control, there is a standard called Git, but its purpose is basically to manage source code, and it is not suitable for binary CAD data.
In my field, we also have a same issue to share our design data(e.g. Photoshop, Illustrator, Sketch....) with others.
I know and used to use several apps to share these files.
Kactus is an OSS software to share your binary files (like png, design files)
And you can see the difference between previous and current change.
Abstract Notebooks | Bring transparency to your design process
Abstract is basically same as Kactus.
They allow us to share Sketch file ONLY.
Because Sketch file consists of xml based. So they can control the difference.