Bite my nails, haven't used clippers in literally over a decade, I just bite my finger-nails into shape when they get too long and as for toes pick and tear them with my hands-which i find incredibly satisfying for some reason even when I'm nipping in-grown in the bud and it ends up bleeding. I also compulsively rub my eyes and pick out that "eye-goo" that forms under eyelids. The same kind of stuff that crusts over as you sleep and makes it like "sand" in your eyes, except during the day when it's not dry. Never in public, though. It's probably not great to do healthwise and looks gross to people, but it's so satisfying. I do it without thinking and catch myself doing it on pretty much a daily basis.

I also consume smoke regularly, these days only medicinal cannabis (though I plan to take a long break here soon), it helps me cope with some things better than traditional meds ever could or did and with fewer downsides, however it's still rough on the lungs (orally taken oils and the like aren't so great for me with their long onset that can vary based on lots of factors, I need the rapid onset of smoke for it to be effective). Before that and partly during that though I also used to smoke tobacco a lot, for like 15 years, quit and relapsed a few times, but have been tobacco-free now for a while. I feel I finally managed to beat that addiction, thank the Lord.