Have

Thraben Inspector

When Thraben Inspector enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Springleaf Drum

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

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Ornithopter

Frogmite

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

Ancient Den

Seat of the Synod

Myr Enforcer

Razortide Bridge

Razortide Bridge enters tapped.
Indestructible
{T}: Add {W} or {U}.

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}.

Gingerbrute

Haste (This creature can attack and {T} as soon as it comes under your control.)
{1}: Gingerbrute can't be blocked this turn except by creatures with haste.
{2}, {T}, Sacrifice Gingerbrute: You gain 3 life.

Thoughtcast

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

Plains

Spire Golem

Affinity for Islands (This spell costs {1} less to cast for each Island you control.)
Flying

Of One Mind

This spell costs {2} less to cast if you control a Human creature and a non-Human creature.
Draw two cards.

Razor Golem

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