MusicBrainz only offers the 3 most common vinyl sizes to chose from in the tracklist tab's format dropdown menu: 7", 10" and 12". But there are many other sizes available. I'm not talking about custom, flexi or lathe cuts; I'm talking about mass-produced releases.

Discogs has nearly 3000 releases on 8" vinyl:
https://www.discogs.com/search/?format_exact=Vinyl&format_exact=8%22

1600 on 6" vinyl
https://www.discogs.com/search/?format_exact=Vinyl&format_exact=6%22

Nearly a 1000 each for 5" and 16" vinyl:
https://www.discogs.com/search/?format_exact=Vinyl&format_exact=5%22
https://www.discogs.com/search/?format_exact=Vinyl&format_exact=16%22

And hundreds more in other sizes like 3", 4", 9" and 11".

Here's an article on other odd-sized vinyl that MusicBrainz currently wouldn't be able to document properly:
https://thevinylfactory.com/features/freaky-formats-the-odd-sized-records-you-never-knew-existed/

Could at least the top 4 mentioned here be added? 8", 6", 5" and 16"?