Rayquaza already has the advantage of being a legendary Pokmon with a huge fanbase, but its Mega form takes that appeal even further with a longer, more explosive body shape and a sense of movement that suits the full art format perfectly
Sorcery Color tag templates(None) Relearn Return target instant or sorcery card from your graveyard to your hand
The big appeal is that its a cheap commander that can be paired with others that have the partner keyword, allowing you to dive into other colors that complement Thrasioss main ability
The other thing to watch for are the number of cards your opponents have in hand
Beyond the names and creatures youd expect, this extends to creatures such as Bill the Pony
So when creating cards, Wizards designers might not consider whether a card might be banned in Commander, since there are other formats where that card could be played