You can basically drop the IPRE crew into any universe and make it canon-consistent by having it be one of the places they visit during Stolen Century. Voltron has canonical alternate realities meaning it can also coexist with just about any other universe. Part of me says Voltron/TAZ crossover but another part of me says nothing would top the first moment when the Starblaster drops into the plane just as Voltron sails past and they all stare at each other in mutual bewilderment