Anyone with the Infinite Gauntlet or a cosmic cube or two has the potential do it. Either Eternity or Mistress Death could do it by themselves. I'd like to see the Collector decide that he wants to add to his collection. So he decides to recruit Dr. Doom, IW Thanos, and Annihilus. After the stop Luthor they turn on each other. Maybe try and offer a bribe of some sort to Galactus if he agrees to help.