Worn Powerstone

This artifact enters tapped.
{T}: Add {C}{C}.

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.

Planar Portal

{6}, {T}: Search your library for a card, put that card into your hand, then shuffle.

Grim Monolith

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

Belbe's Portal

As this artifact enters, choose a creature type.
{3}, {T}: You may put a creature card of the chosen type from your hand onto the battlefield.

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.

Voltaic Key

Boil

Earthquake

Earthquake deals X damage to each creature without flying and each player.

Power Matrix

{T}: Target creature gets +1/+1 and gains flying, first strike, and trample until end of turn.

Temporal Aperture

{5}, {T}: Shuffle your library, then reveal the top card. Until end of turn, for as long as that card remains on top of your library, play with the top card of your library revealed and you may play that card without paying its mana cost. (If it has X in its mana cost, X is 0.)

Covetous Dragon

Flying
When you control no artifacts, sacrifice this creature.

Credit Voucher

{2}, {T}, Sacrifice this artifact: Shuffle any number of cards from your hand into your library, then draw that many cards.

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Mountain

Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Tangle Wire

Fading 4 (This artifact enters with four fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
At the beginning of each player's upkeep, that player taps an untapped artifact, creature, or land they control for each fade counter on this artifact.

Wildfire

Each player sacrifices four lands of their choice. Wildfire deals 4 damage to each creature.