My handhelds of choice are the Analogue Pocket, the AYN Odin, and the Steam Deck. All three of them are awesome in their own way, and honestly I’m happy there are so many cool options nowadays for portable gaming.
Throwing them into a big box marked “FREE” and putting that outside on the curb is probably the least amount of effort.
Other than that, donating them, selling them to a second hand bookstore, or finding a local Little Free Library and adding to their collection is your best bet.