Playing music on my guitar. Even if it's just hitting notes and making noise for the sake of making noise. When I'm depressed, I find it very hard to find the energy or motivation to play (I also write all original material so when I'm not feeling creative it can be really frustrating when I pick up my guitar and end up getting fed up and quitting after 5 minutes) sometimes I'll spend 5 months without even picking up a guitar, but like magic, eventually the energy comes back and I find myself standing in front of my amplifier jamming out for hours at a time and it feels amazing.

Sometimes journaling and writing poetry can be really nice as well, but often I find my writings start out positive but then start becoming dark and contribute to negative moods / thoughts so I have to kind of self monitor and know when to stop writing myself into a bad feedback loop.