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.
This is a bit of an older video, but it shows the sheet based collection management in the second half of the video: http://youtube.com/watch?v=45TGtUQry6Q