Voltaic Key

Myr Enforcer

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

Phyrexian Processor

As this artifact enters, pay any amount of life.
{4}, {T}: Create an X/X black Phyrexian Minion creature token, where X is the life paid as this artifact entered.

Kelpie Guide

{T}: Untap another target permanent you control.
{T}: Tap target permanent. Activate only if you control eight or more lands.

Grim Monolith

This artifact doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{4}: Untap this artifact.

Frogmite

Tolarian Academy

{T}: Add {U} for each artifact you control.

Whir of Invention

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

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.

Sol Ring

Island

Blinkmoth Urn

At the beginning of each player's first main phase, if this artifact is untapped, that player adds {C} for each artifact they control.

Riptide Replicator

As this artifact enters, choose a color and a creature type.
This artifact enters with X charge counters on it.
{4}, {T}: Create an X/X creature token of the chosen color and type, where X is the number of charge counters on this artifact.

Minion

Phyrexian Colossus

This creature doesn't untap during your untap step.
Pay 8 life: Untap this creature.
This creature can't be blocked except by three or more creatures.

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.