(Source) Endymion's Pendulum Effect does not count Mythical Beast cards in your Pendulum Zones
On top of that, if you control four or more humans, each of them gets an additional +2/+2 buff, which can quickly turn the tide of the game and often becomes a game-ending threat
The current iteration of the MTGO client features the worst interface design since the 90s and even then I am pretty sure that Microposes Magic: The Gathering computer game from the late 90s featured better design than this
Arc-V features Action Cards, Spell/Trap Cards that are physically picked up in the series' unique Action Duels, which are not possible to perform in real life
Key to the City is nifty in that you can use it to discard an Equipment card that you can reanimate with Ratonhnhaktons ability, and later on it can even draw you cards
Valiant Our fourth keyword to learn is Valiant