My FTC team transitioned from Fusion 360 to Onshape for CAD over the summer, and to take full advantage of Onshape’s configuration and scripting capabilities (we needed some practice as well), we made a bunch of general mechanical components that we thought could be useful in the coming season.
These include power transmission components (gears, bevel gears, sprockets, etc.), as well as featurescripts to create general belt and chain paths. My personal favorite is a pocketing script that builds a sketch from the ground up, enabling features like variable strut widths.
The document can be found here. I hope some people will find it helpful.