Mirri's Guile

T: Add C. 2, T: Scry 1, then you may reveal the top card of your library. If a basic land card is revealed this way, put it onto the battlefield tapped. Activate only if an opponent controls at least two more lands than you.

All Sliver creatures get +1/+1 for each other Sliver on the battlefield.

This artifact enters with X charge counters on it. Whenever a player casts a spell with mana value equal to the number of charge counters on this artifact, counter that spell.

Metalcraft — T: Add one mana of any color. Activate only if you control three or more artifacts.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) Whenever you cast a noncreature spell, create a 1/1 white Monk creature token with prowess.

T: Add one mana of any type that a land you control could produce.

Commander ninjutsu UB (UB, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand or the command zone tapped and attacking.) Whenever a Ninja you control deals combat damage to a player, reveal the top card of your library and put that card into your hand. Each opponent loses life equal to that card's mana value.