Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Metalspinner's Puzzleknot

When this artifact enters, you draw a card and you lose 1 life.
{2}{B}, Sacrifice this artifact: You draw a card and you lose 1 life.

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.

Mox Opal

Quicksilver Lapidary

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

Myr Battlesphere

When this creature enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Myr Retriever

When this creature dies, return another target artifact card from your graveyard to your hand.

O-Naginata

This Equipment can be attached only to a creature with power 3 or greater.
Equipped creature gets +3/+0 and has trample.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Oblivion Stone

{4}, {T}: Put a fate counter on target permanent.
{5}, {T}, Sacrifice this artifact: Destroy each nonland permanent without a fate counter on it, then remove all fate counters from all permanents.

Revoke Existence

Peace Strider

When this creature enters, you gain 3 life.

Pentad Prism

Sunburst (This artifact enters with a charge counter on it for each color of mana spent to cast it.)
Remove a charge counter from this artifact: Add one mana of any color.

Phyrexian Revoker

As this creature enters, choose a nonland card name.
Activated abilities of sources with the chosen name can't be activated.

Pyrite Spellbomb

{R}, Sacrifice this artifact: It deals 2 damage to any target.
{1}, Sacrifice this artifact: Draw a card.

Ratchet Bomb

{T}: Put a charge counter on this artifact.
{T}, Sacrifice this artifact: Destroy each nonland permanent with mana value equal to the number of charge counters on this artifact.

Sandstone Oracle

Flying
When this creature enters, choose an opponent. If that player has more cards in hand than you, draw cards equal to the difference.

Sculpting Steel

You may have this artifact enter as a copy of any artifact on the battlefield.

Double Masters