Eye of Ramos

{T}: Add {U}.
Sacrifice this artifact: Add {U}.

Sea Scryer

Unblinking Observer

{T}: Add {U}. Spend this mana only to pay a disturb cost or cast an instant or sorcery spell.

Machine God's Effigy

You may have this artifact enter as a copy of any creature on the battlefield, except it's an artifact and it has "{T}: Add {U}." (It's not a creature.)
{T}: Add {U}.

Volshe Tideturner

{T}: Add {U}. Spend this mana only to cast an instant or sorcery spell or a kicked spell.

Blue Mana Battery

{2}, {T}: Put a charge counter on this artifact.
{T}, Remove any number of charge counters from this artifact: Add {U}, then add an additional {U} for each charge counter removed this way.

Chronatog Totem

{T}: Add {U}.
{1}{U}: This artifact becomes a 1/2 blue Atog artifact creature until end of turn.
{0}: This creature gets +3/+3 until end of turn. You skip your next turn. Activate only once each turn and only if this permanent is a creature.

Lapis Orb of Dragonkind

{T}: Add {U}. When you spend this mana to cast a Dragon creature spell, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Silver Myr

Karfell Harbinger

{T}: Add {U}. Spend this mana only to foretell a card from your hand or cast an instant or sorcery spell.

Sky Diamond

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

Alexi, Zephyr Mage

{X}{U}, {T}, Discard two cards: Return X target creatures to their owners' hands.

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on this artifact.
At the beginning of each upkeep, put an hour counter on this artifact.
When the twelfth hour counter is put on this artifact, shuffle your hand and graveyard into your library, then draw seven cards. Exile this artifact.