USDB Plus by mjhalwa

This Add-on provides the following features:

• Categorize songs using colors to e.g. highlight your collection, display song status or apply quality measures. Visible in search results and on the song detail page.
  
• Share categories by loading from JSON raw file hosted on your favorit cloud platform like Github (https://raw.githubusercontent.com/...) or Dropbox (https://dl.dropboxusercontent.com/...)
  
• Display song IDs and Covers while browsing Search Results
  
• Display Metatags from USDBSyncer while browsing Search Results
  
• Listen into song samples while browsing Search Results
  
• Use on Smartphones (with "Firefox Nightly" App)
  
• Disable accidential redirects by touching search result rows on mobile browsers
  

examples for colorizable categories:

• (the original intention) display the status of songs "done" (=download and play), "todo" (=songs I want to checkout next), "challenging" (=songs that require a higher degree of effort to make them playable and are currently broken in some way)
• divide workload between friends with a category per friend
• display a quality measure with categories like "video missing", "bad audio", "wrong GAP", etc.

Examples for the JSON configuration file structure can be found at https://github.com/mjhalwa/usdb_plus/tree/main/examples

Note: (at least on Android) this App seems currently only to be supported by the "Firefox Nighly" App