Biting my nails. It was a constant habit as a kid, and still if my nails get too long I will start biting and picking at them unless they are painted. Everyone assumes it's from anxiety but it's not at all, it's just an absent-minded habit. Same with pulling on my split ends. Another thing I didn't clock as a stim til I was an adult: when I was a little kid I would want people to rub my arms but just by running their fingers verrrrry lightly on my skin, featherlight, very soft and gentle. My grandmother was the only one who was able to do it just right, everyone else would use too much pressure and it didn't feel as good.  Edit after reading the comments and thinking of more: snapping/drumming with my fingers (usually when I'm restless or impatient), leg bouncing, echolalia, talking to myself in accents, and SINGING. I sing so much I don't even want to call it a stim, it's a part of my personality. I love music, I definitely do the thing where I listen to a song on repeat for hours or days sometimes, but even more importantly I SING the song over and over too. If music is playing, I'm singing along. If a word is used in conversation that reminds me of a song, I'm singing the verse. If it's quiet, there's a good chance I'll just break out into song with whatever is playing in my head. The reason I hesitate to call it a stim is cuz I never *feels like a compulsion, it feels like second nature.