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}

Thoughtcast

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

Forging the Anchor

Look at the top five cards of your library. You may reveal any number of artifact cards from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.

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.

Moonsnare Prototype

{T}, Tap an untapped artifact or creature you control: Add {C}.
Channel — {4}{U}, Discard this card: The owner of target nonland permanent puts it on their choice of the top or bottom of their library.

Cranial Plating

Equipped creature gets +1/+0 for each artifact you control.
{B}{B}: Attach this Equipment to target creature you control.
Equip {1}

Mistvault Bridge

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

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.

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.

Treasure Vault

{T}: Add {C}.
{X}{X}, {T}, Sacrifice this land: Create X Treasure tokens.

Silverbluff Bridge

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

The Reality Chip

You may look at the top card of your library any time.
As long as The Reality Chip is attached to a creature, you may play lands and cast spells from the top of your library.
Reconfigure {2}{U} ({2}{U}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Karn, Scion of Urza

+1: Reveal the top two cards of your library. An opponent chooses one of them. Put that card into your hand and exile the other with a silver counter on it.
−1: Put a card you own with a silver counter on it from exile into your hand.
−2: Create a 0/0 colorless Construct artifact creature token with "This token gets +1/+1 for each artifact you control."

Springleaf Drum

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

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.

Sojourner's Companion

Affinity for artifacts
Artifact landcycling {2} ({2}, Discard this card: Search your library for an artifact land card, reveal it, put it into your hand, then shuffle.)

Welding Jar

Sacrifice this artifact: Regenerate target artifact.

Darksteel Citadel

Myr Enforcer

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