Well, first of all, the "Infinity" phrase found in many Marvel characters comes from "Marvel Super Heros" and isn't specifically related to the IMT.
As for old Infinity creations, basically everything is on the main website and if it's not there then either it's obsolete (e.g. Cobra Commander by Scar) because of a newer verison on works, permission revoked (e.g. the other Beast originally by Slotman, edited by Acey), or just forgotten (forget which ones these might be.)
Hope this helps.