https://duckduckgo.com/?t=ffab&q=parmesan+rind+uses&ia=web

From the top result (Treehugger):

1. Throw them into tomato sauce when cooking. They’ll impart some flavor. Pull them out and discard when the sauce is done cooking.
2. Place them in a jar, pour olive oil over them (perhaps add some garlic cloves, too – but if you add garlic, make sure to keep the oil refrigerated) and make parmesan-infused olive oil. Great for dipping bread into.
3. Throw them into bean soups or minestrone. Discard the rinds before serving.
4. Throw them into the pot when you’re making stock.
5. Add to stew. Remove rinds before serving.
6. Use them to flavor steamed artichokes. Add some chicken broth, onion and lemon juice and a cheese rind or two, and it's a delicious broth!
7. Put a rind in the pot when you’re cooking risotto or other rice. Remove the rind before serving.
8. Make a parmesan broth for cheese-filled pastas like ravioli. You can try the Bitchincamero's recipe for ricotta & pea ravioli in parmesan broth or just use the recipe for inspiration for your own pasta in Parmesan broth.
9. Try The Novice Chef's Panera-inspired recipe for tomato, cheese and bread Soup.
10. If the rind is pure cheese (with no waxy coating), you can grill the rind until it becomes soft and chewy, put it on a piece of crusty bread, and eat.