Alexander's Hetaroi
Deity
The only thing I could think of is spreading your corporation to all other Civs and control a monopoly on a particular type of corporation, but that does sound close to the religious victory.One last thing I'd like to see make it into Civ6 before the book's closed is an Economic Victory, and possibly corporations. I'm all about asymmetry in 4x games, so various victory conditions naturally appeals to me. I'm not sure how they could implement such a feature without it being a "accumulate piles of gold to win" scenario, but I'm sure they could come up with something interesting.
Maybe to differentiate it you could get traders involved and send trade routes to a city in order for one of your franchises to go to there. If there happens to be a competing corporation you could eventually buy them out if you become more successful maybe by better trade yields.