There were the Fully Finished Outtakes that were leaked earlier this year, but I can't remember off the top of my head how many exactly there were-- just that it was over 50 iirc. As far as Auction Masters, you're going to have to be more specific. I'm pretty sure a few outtake/masters have been auctioned off lol.
The additional BtB tracks have also been released by No Label(Watchtower), Misterclaudel (Or their RS subsidiary), Moonchild and more. It’s not like a bootlegger or two wouldn’t exploit them if they could.