Mage Slayer

Whenever equipped creature attacks, it deals damage equal to its power to the player or planeswalker it's attacking.
Equip {3}

Razia, Boros Archangel

Flying, vigilance, haste
{T}: The next 3 damage that would be dealt to target creature you control this turn is dealt to another target creature instead.

Rumbling Slum

At the beginning of your upkeep, this creature deals 1 damage to each player.

Savage Twister

Savage Twister deals X damage to each creature.

Sludge Strider

Whenever another artifact you control enters or leaves the battlefield, you may pay {1}. If you do, target player loses 1 life and you gain 1 life.

Arsenal Thresher

As this creature enters, you may reveal any number of other artifact cards from your hand. This creature enters with a +1/+1 counter on it for each card revealed this way.

Balefire Liege

Other red creatures you control get +1/+1.
Other white creatures you control get +1/+1.
Whenever you cast a red spell, this creature deals 3 damage to target player or planeswalker.
Whenever you cast a white spell, you gain 3 life.

Battlegate Mimic

Whenever you cast a spell that's both red and white, this creature has base power and toughness 4/2 until end of turn and gains first strike until end of turn.

Boros Guildmage

{1}{R}: Target creature gains haste until end of turn.
{1}{W}: Target creature gains first strike until end of turn.

Planechase