As for the other three (Evolution SageEvolution Sage, Metallic MimicMetallic Mimic, and RealmwalkerRealmwalker), while they're creating synergy with the deck, I would have preferred something a little more oceanic, or at least from Ixalan itself, like Roaming ThroneRoaming Throne, for example
That being said, however, there is one card that is proving to be a problem all over the place
thecardbazaar.com.au
The Colourless type in the Pokmon TCG includes Normal, Flying and Dragon Pokmon seen in the video games, although more recent Dragon cards - from 2012s Dragons Exalted expansion onwards - have been classified as their own separate type of Pokmon card
Its cheap, easy to use, and in white, filling your graveyard is something you actively want to be doing most of the time, to take advantage of whites great recursion pieces
The creature side of this is decidedly less impressive because it starts inefficiently and asks you to do something that even in Blue-Green youre not going to do so often that the Hart will just become absolutely massive