Personally: Hiking, biking, photography, DnD, and fixing things.
It sounds like a lot (because it is lol) but with ADHD having a group of hobbies I can orbit around (especially if they can overlap (like these ones))can help me avoid diving into too many new hobbies.
Solo game developer (and fellow ADHD-haver) here. I do the coding, 3d modelling, animations, and even a little bit of sound design. It's all incredibly time-consuming though.
Ooh what are you on with atm? I'm embroiled in a minimalist city builder thing and just got to the part where I need to learn to animate things, which I have been full-on dreading.
I use Blender for most of my animating needs. And using Houdini Indie has helped me to start thinking about asset creation in a more procedural way, which helped when I needed to make my own building generator.
This week I've been trying to figure out a way to load user-created characters and skins in a multiplayer game. My character setup scripts seem to work, but still a ton of hurtles to get over.