You might find drums and percussion instruments to your liking. I had a good friend who likely had ADHD, or something like it, with over-active mind, constantly shifting attention/focus, expressed in his manner of speech and fidgeting (always jumping legs up and down). He was a drummer, and it was very noticeable that when he played drums, his mind could stay focused for hours, and even his fidgeting stopped. It was like his nervous energy would get channelled out of his body into the music.