A daily new-music feed
Every morning the build reads Last.fm, ListenBrainz, MusicBrainz, Bandcamp, Deezer, radio playlists and a few dozen blogs, scores what it finds against one listener's taste, and lists the best of it here. Press play on any card, or space, and it plays on through the list.
Sign in with Google and the Keep / Skip buttons appear: Keep files a track into a year playlist in your own YouTube library, Skip hides it for good. Install the site as an app for a full-screen deck with lock-screen controls.
Cleanup
Every Keep first checks the target playlist, so the same video is never added twice by the site. The daily build scans all year playlists for the exact same video appearing twice in a year (an extra copy: remove it, one stays) or in two different years (a filing question: the verified year marks the wrong copy). It also notes every track YouTube Music greys out in the US (label rights, a withdrawn upload, a region lock) and looks for another upload of the same song that streams here, the audio track first: not streamable here in the kind menu, where a swap adds the counterpart and removes the dead copy. A removal costs 50 YouTube API units and a swap 100, so this is a job for a few minutes a day; what you clean is remembered on every device you sign into.
Scan a year now
The report above is from the last build; a live scan reads one playlist as it is right now (1 unit per 50 tracks) and catches today's double-taps.