Sensory Board

This is something Junior doesn't use much anymore but when he was younger it was used daily.
It fits in his lap or on his wheelchair tray so anytime he moves his hands he is touching a different texture.
It is very simple to make.
We used a piece of foam board as the base, cut to whatever size you need.
Then glue on different textured items. For Junior's, I used a piece of a grass rug, the insert from a box of candy(turned upside down), a piece of rubber non skid shelf liner, a couple of brushes, duct tape(folded into little flaps), some crate paper, and a piece of floor puzzle.
You could use pretty much anything to make it work for your child depending on your their needs and abilities. The sky is the limit with the sensory board, you could even attach some sensory toys to it.