Wall of Denial

Defender, flying
Shroud (This creature can't be the target of spells or abilities.)

Crystal Barricade

Defender (This creature can't attack.)
You have hexproof. (You can't be the target of spells or abilities your opponents control.)
Prevent all noncombat damage that would be dealt to other creatures you control.

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Fog Bank

Defender (This creature can't attack.)
Flying
Prevent all combat damage that would be dealt to and dealt by this creature.

Interplanar Beacon

Whenever you cast a planeswalker spell, you gain 1 life.
{T}: Add {C}.
{1}, {T}: Add two mana of different colors. Spend this mana only to cast planeswalker spells.

Commodore Guff

At the beginning of your end step, put a loyalty counter on another target planeswalker you control.
+1: Create a 1/1 red Wizard creature token with "{T}: Add {R}. Spend this mana only to cast a planeswalker spell."
−3: You draw X cards and Commodore Guff deals X damage to each opponent, where X is the number of planeswalkers you control.
Commodore Guff can be your commander.

Silent Arbiter

No more than one creature can attack each combat.
No more than one creature can block each combat.