Legalities I Know All, I See All is not legal in any format
Squirrel Girl gets straight to the point on producing squirrels, and the absence of a on the activated ability is well nuts
Though the Marvel Secret Lair release was horribly bungled, the fact that fans have been able to share their bonus cards so quickly does illustrate the one big advantage of the new Secret Lair model (from the perspective of players that is)
12 Nicol Bolas, The Ravager One Part Dragon, One Part Planeswalker Nicol Bolas, the Ravager is a double-sided Commander, entering the battlefield as a legendary creature and capable of later transforming into a Planeswalker
This enter the battlefield effect would normally cost you two mana on its own, so the fact that it's tacked onto Siege Rhino provides incredible value
The ability to ink the card makes it hard for it to ever become dead weight, making it a strong option to include in any Steel deck