Kyorge and groundon are more likely to be primal forms instead of megas but I don’t wanna argue with you but it would be funny for a mega dundunsparce and it’s called mega dundundunsparace
I think porygon Z should get a mega and it’s more of glitched form. Especially the game name being Pokémon legend Z-A and also a mega dragon eevee but the mega form has been lost in Tim the mega doesn't appear in any other game but if we use celebi and Dialga to travel back to time we get a mega fragment a mega fragment basically gives the mega Pokémon 5 turns and turns back to normal it disappears once you use it.