Plagon, Lord of the Beach Plagon, Lord of the Beach is going to be a strong option in the toughness matters space
The former is a 2/4 that will attack and block as a 4/4 and then tap for any color of mana, and then gain 3 life on arrival to the battlefield
That aside, Magus of the Bridge is Open the Graves with the downside of Bridge from Below
I not only expect to see tons of these in sideboards but also creature strategies to be built around this powerful artifact
If you have the mana to cast this card, chances are you don't really value the mana doubling that much on its own
And EDH, in particular, lends itself to self-expression. Familiarity with the various Magic formats and rules is key to understanding the appeal of alters, proxies, and overlays