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.

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Teferi, Time Raveler

Each opponent can cast spells only any time they could cast a sorcery.
+1: Until your next turn, you may cast sorcery spells as though they had flash.
−3: Return up to one target artifact, creature, or enchantment to its owner's hand. Draw a card.

Thoughtcast

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Draw two cards.

Kor Firewalker

Protection from red
Whenever a player casts a red spell, you may gain 1 life.

Chalice of the Void

This artifact enters with X charge counters on it.
Whenever a player casts a spell with mana value equal to the number of charge counters on this artifact, counter that spell.

Soul-Guide Lantern

When this artifact enters, exile target card from a graveyard.
{T}, Sacrifice this artifact: Exile each opponent's graveyard.
{1}, {T}, Sacrifice this artifact: Draw a card.

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.

Plains

Damping Sphere

If a land is tapped for two or more mana, it produces {C} instead of any other type and amount.
Each spell a player casts costs {1} more to cast for each other spell that player has cast this turn.

Darksteel Citadel

Razortide Bridge

This land enters tapped.
Indestructible
{T}: Add {W} or {U}.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — This Saga gains "{T}: Add {C}."
II — This Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This token gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Shadowspear

Equipped creature gets +1/+1 and has trample and lifelink.
{1}: Permanents your opponents control lose hexproof and indestructible until end of turn.
Equip {2}

Memnite

Nettlecyst

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each artifact and/or enchantment you control.
Equip {2}

Portable Hole

When this artifact enters, exile target nonland permanent an opponent controls with mana value 2 or less until this artifact leaves the battlefield.

Meddling Mage

As this creature enters, choose a nonland card name.
Spells with the chosen name can't be cast.

Aether Spellbomb

{U}, Sacrifice this artifact: Return target creature to its owner's hand.
{1}, Sacrifice this artifact: Draw a card.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard this card: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Ingenious Smith

When this creature enters, look at the top four cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Whenever one or more artifacts you control enter, put a +1/+1 counter on this creature. This ability triggers only once each turn.

Dispatch

Tap target creature.
Metalcraft — If you control three or more artifacts, exile that creature.

Metallic Rebuke

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Counter target spell unless its controller pays {3}.

Hallowed Fountain

({T}: Add {W} or {U}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Void Mirror

Whenever a player casts a spell, if no colored mana was spent to cast it, counter that spell.

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile this artifact: Exile all graveyards. Draw a card.

Seachrome Coast

This land enters tapped unless you control two or fewer other lands.
{T}: Add {W} or {U}.

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When this creature enters, draw two cards.