Hivemind is something I've thought about. A player in a game I'm running now was reflavoring GOO as an A.I. pact but we ended up just making an A.I. pact that can summon an "altar" that is a terminal with buffs/debuffs. I've also had a postapocalyptic game where the remnant civilization was run by powerful merchantile conglomerates and there was going to be a Corporation pact for those magically contracted with the oligarchy.
People have mentioned it before, but the way psionics was described in 4e, it developed as the universe's antibiotic reaction to Far Realm incursion. Any anti-Far Realm organization, being, or concept works a patron in a way that kinda already fits vanilla DnD.