Much as the language I have used here is pretty biased, there is no right or wrong
My only concern when it comes to Mewtwo is how to power it up consistently, turn after turn effectively
It allows for interesting builds and mechanics, and that makes it one of the most popular choices in this list
Maybe you could use a crudely drawn MS Paint picture of a card
White/Black: Revolt Although not identified as such, Minthara, Merciless Soul is basically a creature that users the Aether Revolt mechanic Revolt by gaining you experience counters at the end of your turn if somethings left your battlefield (and note that this includes Treasure tokens, and also triggers through blink effects)
In theory, you could play Goblin Engineer as a value card in some sort of Affinity-style artifact aggro deck or maybe in some sort of artifact reanimator deck, as an Entomb alongside cards like Trash for Treasure and Refurbish