For my learning-themed sensory bin I started with Lakeshore’s Translucent Letters and a variety of miniature items (each of which corresponds to each letter). I got some clear plastic rocks and small puck lights and added them all to the sensory bin. Kids can play in the sensory bin in any way they’d like, but one of the things they can do is match the letters to their corresponding item. I find that kids who prefer structured activities are better able to address their sensory system with bins like this because they don’t feel as bored.
You can find the rest of my themed sensory bins here.
And you can find the rest of my learning-themed materials here.