Gearseeker Serpent

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{5}{U}: This creature can't be blocked this turn.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Thoughtcast

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

Reverse Engineer

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

Retraction Helix

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Meeting of Minds

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Draw two cards.

Metallic Rebuke

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Counter target spell unless its controller pays {3}.

Frogmite

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

Mistvault Bridge

This land enters tapped.
Indestructible
{T}: Add {U} or {B}.

Phyrexian Walker

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Ornithopter

Myr Enforcer

Seat of the Synod

Tooth of Chiss-Goria

Flash
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{T}: Target creature gets +1/+0 until end of turn.

Steelfin Whale

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Whenever an artifact you control enters, untap this creature.

Silverbluff Bridge

This land enters tapped.
Indestructible
{T}: Add {U} or {R}.

Elusive Spellfist

Whenever you cast a noncreature spell, this creature gets +1/+0 until end of turn and can't be blocked this turn.