The Beatles (includes GB/US/Japan versions, stereo/mono sets, compilations and bootlegs) and then King Crimson, Peter Hammill/Van Der Graaf, Emerson, Lake & Palmer (includes Keith's Nice & solo works) and Hawkwind (includes Robert Calvert catalogue).
Although I’ve never counted them it would probably be James Last for albums
But it will never beat my collection of Bowie singles totalling more than 100
As a side note my mate has every vinyl edition by Pink Floyd . All the import rarities, all the singles and all the box sets .. Thing his he hasn’t a TT so all are still in the original condition of brand new ..
Be worth a few bob now …I think it’s also the same with Black Sabbath ..
Daren't count 'em all. If you include the solo stuff, I've got 53 Floyd albums (and that's counting box sets as one), though there are a couple of duplicates. Probably about the same number on CD as well.
7 copies of Mrs Mills 'Sunshine/Bobbykins'
3 copies of Clive Dun 'Pinocchio Eventyr'
4 copies of Bill Tarney 'Time for love'
17 copies of St. Winifreds chior 'My very own party record' + so many white labels and EP's I've lost count.
Beatles - all vinyl singles, EPs, albums, CDs, remastered CDs, Mono and Stereo Box Sets, VHS and Film DVDs, Blu-ray films and DVD and CD Anthology - and some US versions of them all. No way I’m going to count them
Genesis - all albums, vinyl and CD, remastered CD and CD/SACD box sets, DVDs, Blu-ray concerts
Peter Gabriel - all albums on CD/Vinyl plus all remastered CD and a variety of DVD/Blu-ray
ELP - most albums on CD plus lot of vinyl and a few box sets as well as individual solo albums from each band member and The Nice.
Steven Wilson - all Porcupine Tree including Bandcamp downloads, CD, Box sets, most also on vinyl and remastered CD. All Blackfield albums, all his solo albums (deluxe box sets)
All The Pineapple Thief albums and DVD/Blu-ray of which there is a surprising amount