Many of my favourite noise boxes are already mentioned (G*Park, Merzbox, Incapacitants, TNB, Parmegiani, Bayle etc.). Here are some other greats that come to my mind:
V/A "Electronic Panorama" 4LP - perhaps the ultimate EA V/A with founders, superstars and even some obscurities. And top notch presentation, hail Philips!
V/A "Revue OU" 4CD/6LP - same words (and some more) for sound poetry.
V/A "Source Records" 3CD - many historically groundbreaking (and some very noisy) recordings here.
Albert Ayler "Holy Ghost" 10CD - Ayler panorama with wide range of material, some incredible, some less so but pretty much all relevant. Really beautiful book and some other miscellanea.
Toru Takemitsu "Film Music by Toru Takemitsu" 7CD - can't read the liner notes but the music speaks more than enough. Some really sublime moments there. Was there a complete Takemitsu soundtrack set with a couple of dozen discs?
Tangerine Dream "The Bootleg Box Set Vol 1" 7CD - rather rough live recordings from last bearable years of the Tangs. Great airy heaviness in some of the recordings.
From more rock'n'roll side This Heat, Can "Lost Tapes" and BBC Grind Madness are all top stuff.
The discussed VoD stuff can be rather iffy. I have bothered to get just a few of them, John Duncan and Etant Donnes sets are awesome.
Edit: Pain Jerk "Cacophony of a Thousand Pleasures", perhaps the best noise single multi-release?