All the master tapes for all the studio albums, barring 7 of the 8 tracks from Technical Ecstasy are apparently missing. Master tapes of outtakes from the first four albums were found in a vault in the UK somewhere about 10 years ago - these were issued on the Sanctuary deluxe editions of the first three albums shortly after that, and the more recent super deluxe edition of Vol. 4, which features Steven Wilson remixes of the outtakes.
The 1975 show (Asbury Park, NJ, 8/5/75) that Spock Wall (who was the band's live sound engineer, and a consultant on the quad remix of Paranoid) mixed is featured in full on the recent super deluxe edition of Sabotage, though it appears that they were sourced from the low-bitrate mp3s available for purchase on the Wolfgang's Vault website. That version was a remix done in the '90s from the multitracks (without Wall) because all the King Biscuit mixed masters perished in the 1982 DIR vault fire. I'm pretty sure that all that was originally broadcast on KBFH was about 25 minutes, whereas the full show runs in excess of 90 minutes.
Presumably Wolfgang's Vault, having bought all the KBFH assets, have the original multitrack in their possession, though supposedly they want exorbitant rates to license the things they own, which may explain the lossy provenance of their stuff on the recent Sabbath deluxe editions.