At one time Greg had about three dozen pieces, including some of my favorites from Series 4 and 5 (Fatina, Nutlee's Quit). I'm not sure how many he hung on to.
From about 2002 on, previously unseen OS pieces would emerge from the Topps Vault to be auctioned on eBay. These included such iconic pieces as Jail-O, Dull and Band-Ache. The last of these was listed with a $1M BIN at one point. (Eric didn't take the bait.) Maybe 100-something remain unaccounted for, hiding in warehouses, swiped by employees, their whereabouts otherwise unknown.
I have very little current information on who owns what, and I will let the owners volunteer that if they wish.