Barricade Breaker

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Barricade Breaker attacks each combat if able.

Frogmite

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Myr Enforcer

Foundry Assembler

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Memnite

Welding Jar

Sacrifice Welding Jar: Regenerate target artifact.

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Frogmyr Enforcer

Prototype {3}{R} — 2/2 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Mutagenic Growth

({G/P} can be paid with either {G} or 2 life.)
Target creature gets +2/+2 until end of turn.

Bone Saw

Equipped creature gets +1/+0.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Spidersilk Net

Equipped creature gets +0/+2 and has reach. (It can block creatures with flying.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Sojourner's Companion

Affinity for artifacts
Artifact landcycling {2} ({2}, Discard this card: Search your library for an artifact land card, reveal it, put it into your hand, then shuffle.)

Marrow Shards

({W/P} can be paid with either {W} or 2 life.)
Marrow Shards deals 1 damage to each attacking creature.

Briber's Purse

Briber's Purse enters with X gem counters on it.
{1}, {T}, Remove a gem counter from Briber's Purse: Target creature can't attack or block this turn.

Darksteel Relic

Indestructible (Effects that say "destroy" don't destroy this artifact.)

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Zuran Orb

Ornithopter

Mishra's Bauble

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.