Since gen in recent times has been able to introduce a gimmick that is centered around each of the Pokemon types there are, which sadly might not be able to be seen in any other region outside the one that introduced them, which could mainly come from these gimmicks running on a certain Legendary Pokemon. Even if we did see Z Moves, Dynamaxing/Gigantamaxing and Terastalisation again one of these years, the time that happens would be once we next see the regions they were featured in, being remakes of the games from Gens VII-IX. We should not see such games however until there are new Pokemon Types beyond the 18 that there are already, that way those new types can be given a Z Move, Max Move and Terastalisation of their own.