Silent Arbiter

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

Colossus of Akros

Defender, indestructible
{10}: Monstrosity 10. (If this creature isn't monstrous, put ten +1/+1 counters on it and it becomes monstrous.)
As long as Colossus of Akros is monstrous, it has trample and can attack as though it didn't have defender.

Mechanized Production

Enchant artifact you control
At the beginning of your upkeep, create a token that's a copy of enchanted artifact. Then if you control eight or more artifacts with the same name as one another, you win the game.

Vedalken Engineer

{T}: Add two mana of any one color. Spend this mana only to cast artifact spells or activate abilities of artifacts.

Vedalken Archmage

Whenever you cast an artifact spell, draw a card.

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.