I tend to rock back and forth. It looks very mental, I know
I try my best to not do it in front of people, but sometimes It just starts. The only ones to comment on it as of yet are my parent.
I also tend to tap my foot a lot, but it requires me to be seated.
I also tend to pace when I am thinking. I normally follow a specific path chosen by the area I am in.
When I was younger, (mostly in my early teenage years) I was using another way to stimulate myself.
When I was seated I had my hands on my lap and I rocked back and forth following the movement of my hands, going back and forth my quadriceps area
I had no idea as to why I did it back then other than it felt kind of good for some kind of strange reason.
People would of course notice which led to me stopping over the years.
I also used to drum with my hands (or drum sticks if I had some in my hands because I played drums when I was younger) on my lap or other things around me. This could just be because I played drums, who knows.
When I was in elementary school I also used to bite on my pens a lot. Now I have adapted to biting on corks from the milk bottles or what else I can bite on.
I have probably had more ways to stimulate myself over the years, but I cannot recall any specifics.