Ashnod's Altar

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Dross Scorpion

Whenever Dross Scorpion or another artifact creature dies, you may untap target artifact.

Krark-Clan Ironworks

Cauldron of Souls

{T}: Choose any number of target creatures. Each of those creatures gains persist until end of turn. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Myr Turbine

{T}: Create a 1/1 colorless Myr artifact creature token.
{T}, Tap five untapped Myr you control: Search your library for a Myr creature card, put it onto the battlefield, then shuffle.

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Evolutionary Leap

{G}, Sacrifice a creature: Reveal cards from the top of your library until you reveal a creature card. Put that card into your hand and the rest on the bottom of your library in a random order.

Grumgully, the Generous

Each other non-Human creature you control enters with an additional +1/+1 counter on it.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.