When I'm concentrating or even just not really paying attention I have like the opposite of RBF, instead I smile stupidly. I hate it, especially because I don't like my smile. But occasionally I'll suddenly realize that I've been doing it and that my face hurts from smiling that much.
Also whenever I'm in crowded areas I tend to touch my thumb to each of my fingers back and forth. I get anxiety in crowds and it's just a way to deal with that I guess.
I also sometimes randomly whistle saying some words because I have a gap in my teeth. And sometimes I kinda roll words (like how an r is rolled in Spanish). Seems to happen with ts and ds in words occasionally.