Winter Orb

As long as this artifact is untapped, players can't untap more than one land during their untap steps.

Howling Mine

At the beginning of each player's draw step, if this artifact is untapped, that player draws an additional card.

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you.
{T}: Add {C}{C}.

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Unwinding Clock

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Urza, Lord High Artificer

When Urza enters, create a 0/0 colorless Construct artifact creature token with "This token gets +1/+1 for each artifact you control."
Tap an untapped artifact you control: Add {U}.
{5}: Shuffle your library, then exile the top card. Until end of turn, you may play that card without paying its mana cost.

Jeweled Lotus

{T}, Sacrifice this artifact: Add three mana of any one color. Spend this mana only to cast your commander.