This card seems like a slam dunk for Modern Merfolk decks, and likely will make a splash in Izzet Wizards alongside Flame of Anor
Flying You can tap any four untapped artifacts, creatures, and/or lands you control, including creatures you haven't controlled continuously since the beginning of your most recent turn, to pay the additional cost to cast Guardian of the Great Door
My favorite three decks: Blue-Red 4-drop spells : This is the base archetype for UR, and is supported quite well Grixis Control: As the name suggests, this is basically just all the good Grixis removal and card draw combined, with some lands for good measure
When all is said and done, this Belle Ramp deck is very strong and has done quite well from my testing online
That is a fair point, since all those cards are pretty messed up