Goblin Welder

{T}: Choose target artifact a player controls and target artifact card in that player's graveyard. If both targets are still legal as this ability resolves, that player simultaneously sacrifices the artifact and returns the artifact card to the battlefield.

Tinker

As an additional cost to cast this spell, sacrifice an artifact.
Search your library for an artifact card, put that card onto the battlefield, then shuffle.

Myr Battlesphere

When this creature enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Sphinx of the Steel Wind

Flying, first strike, vigilance, lifelink, protection from red and from green

Scuttling Doom Engine

This creature can't be blocked by creatures with power 2 or less.
When this creature dies, it deals 6 damage to target opponent or planeswalker.

Steel Hellkite

Flying
{2}: This creature gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by this creature this turn. Activate only once each turn.

Ruin Grinder

Menace
When this creature dies, each player may discard their hand and draw seven cards.
Mountaincycling {2} ({2}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)