Hi there! I added some useful packages to the starter project and uploaded it on GitHub. Hope that's useful for someone.
Grab it here, let me know if it works :)

https://github.com/daalta/VRChat-Sketchbook-Jam

This is a great idea! We created our own official base repository here: https://github.com/vrchat/VRChat-Sketchbook-Jam
If you fork your add-on version above from this one, then we can handle upstream changes.

That's awesome!

I've incorporated your changes into my repository to fix those import bugs.

I think I'll leave it separate for now (instead of a fork), I assume most participants have access to the project by now.