Highlights of this 266-card mega-set include: Almost every single HERO card, all in one place: Elemental HERO, Destiny HERO, and Evil HERO
In a multicolor deck, however, it can often mean not having access to one of your colors
Shaving off one mana from Card not found seems to do a lot
Additionally having to pick which 3 options to place face down before the battle phase and using them as a strategic resource rather than spamming them leads to much more interesting gameplay
This means that, while your opponents will struggle to keep up with your tempo, you can build up your resources and control the state of the board more efficiently than ever
If you play that card (which is great for a Commander deck) with a Nantuko Shrine in play, you get a huge ooze token as well as myriad squirrel tokens related to the amount of Slime Against Humanity cards in your graveyard