DIY Sensory Blocks - a wonderful sensory toy for your little one, but wouldn't they be GREAT in speech therapy? Close your eyes, touch, now describe how it feels. Use your best vocabulary words for describing!
Could also connect a bunch of locks and put all the keys on a key ring. Lots of pictures of latch, lock, etc ideas for montessori type preschool. This lock one could be made with 2 boards, some o-rings, and some locks from Dollar Store.