Iconography is my personal favorite minimalist practice. Boiling down a concept or object to its bare minimum that can still be represented in a small form-factor, and maintaining continuity in sets of them is incredibly rewarding.
Trackpad doodling is a fun and meditative pain in the ass.
I was up late one night searching for inspiration for designs when I realized that I didn't have to design for a company, but instead an object. Just playing around with my own creativity.
Print is a fun exercise in physicality, and posters are especially fun.