Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is this creature's power.

Encroaching Mycosynth

Nonland permanents you control are artifacts in addition to their other types. The same is true for permanent spells you control and nonland permanent cards you own that aren't on the battlefield.

Memnite

Cryogen Relic

When this artifact enters or leaves the battlefield, draw a card.
{1}{U}, Sacrifice this artifact: Put a stun counter on up to one target tapped creature. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Mishra's Bauble

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

Galvanic Blast

Galvanic Blast deals 2 damage to any target.
Metalcraft — Galvanic Blast deals 4 damage instead if you control three or more artifacts.

Pia's Revolution

Whenever a nontoken artifact is put into your graveyard from the battlefield, return that card to your hand unless target opponent has this enchantment deal 3 damage to them.

Atog

Sacrifice an artifact: This creature gets +2/+2 until end of turn.

Mountain

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Ornithopter

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.