Discogs listing in noise seems more meaningful that in some other genres. I don't know why exactly, but it seems like in mainstream music, there often is A LOT of releases that are not listed in discogs, while with noise and related, sometimes seemed as if there isn't releases small enough to be listed. Or it seems like it.
There are some even quite recent things that didn't make it to discogs, and feel like "forgotten". Its easier to notice when its something you're involved. Like, I have not checked out recently, but if you compare Grunt discography on discogs and on band website, I would think latter is more accurate, but even I can't guarantee every comp track is featured etc. Discogs seemed to be missing Grunt/Jukka Siikala split LP, which really does exists, but was just very small amount sold by Siikala. Old tapes like "Theories of Dream Machinist" (Worthless Human Flesh rec) were never listed at discogs as far as I know. I recall couple others too.
I do own a lot of things that are not at discogs. At some point I was thinking of podcast about Finnish obscurities, where would put snippets of examples of projects very few know or remember. Like how would be project with members of Sadio & Savage Gospel from the 90's sound like? That would not be me and Vekka... What a lot oddity even artists themselves no longer have!
Talking about Hospital prod, there are not only missing number that were not completed, but there are some double used numbers! This applies on early days when there was two guys doing things and I have couple of these early ones that are different releases than it says on discogs. But existence of them is known, at least by the maniac collectors like mr. Fusty C. Just appears that I am only known owner of some of these.