https://koillection.github.io/
https://github.com/benjaminjonard/koillection
From README on github:
Koillection is a self-hosted collection manager created to keep track of physical (mostly) collections of any kind like books, DVDs, stamps, games... As Koillection is meant to be used for any kind of collections, it doesn't support automatic download of metadata. But it offers the possibility to add your own metadata freely.