VGStash
Homepage | PyPI Project Page | License: AGPL-3.0-only
VGStash is a video game collection tracker that gives the user a number of fields to track their games with, including ownership, progress, and notes. It also comes with a set of filters that give users the ability to make meaningful inquiries to their collection.
It also includes a web front-end to display the JSON data you can export with the tool, allowing you to share (and theme) a webpage detailing your game collection.
ZLG's VGStash is a live demonstration of the author's own collection. The colors can be customized to suit the user's preferences.