There are three things that I will favorite a project for:
1. Technical complexity
2. Artistic skill involved
3. Funness/ Effort (I know that is not a word).
I like studios which actually curate stuff

Simple Sandbox (Inspired by SamMerlin's simple water physics)
Formula Pen. This is a highly complex racing sim, in 2D of course. (Or possibly 3D, who knows?)
Don't click the Button.
Remixing Cool Stuff (R)