Show HN: A collection manager and marketplace for physical retro games

I’m building sumthings.com, a product-first marketplace and collection manager for all games, with a special focus on retro. You can track your collection, mark wanted items to get notified when sales pop up, and browse today’s listings. Things are still early and changing fast, so I’d love your feedback on what’s useful, what’s missing, and what would make this most valuable for collectors.