This list is meant to include films that are completely or largely created via stop-motion animation, whether it's claymation, puppetry, paper cutouts, sand on glass, or any other physical media normally used. For occasional bits of stop-motion animation in largely live-action films, please see the Stop-Motion Demons (Etc.) list linked below.
For fans of gaming, I highly recommend The Dream Machine, a point-and-click adventure about exploring other people's dreams. I've played through it in its entirety myself, and the whole thing is made with stop-motion techniques and animations.
Not on Letterboxd:
+ Olipop's stop-motion short introducing their winter yeti mascots
+ The Fastest and Funniest LEGO Star Wars Story Ever Told part 1 and part 2
Companion lists:
+ Practical Effects
+ Stop-Motion Demons (Etc.)