I am looking for a feature (add-on) that creates finger joints between two or more bodies. Laser Joint ("LJ"), a feature script for Onshape by Arul Suresh (Stanford U), is the most complete and flexible tool I have had the pleasure to work with. I have included some of my work to demonstrate it's usefulness.
Aquarium Lights & Controller
Spray Booth
Wire Dispenser
Laser Joint UI