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}

Myr Enforcer

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

Cranial Plating

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

Pithing Needle

As this artifact enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Darksteel Citadel

Glimmervoid

At the beginning of the end step, if you control no artifacts, sacrifice this land.
{T}: Add one mana of any color.

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.)

Etched Champion

Metalcraft — This creature has protection from each color as long as you control three or more artifacts.

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.

Memnite

Springleaf Drum

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

Razortide Bridge

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

Tormod's Crypt

{T}, Sacrifice this artifact: Exile target player's graveyard.

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.

Welding Jar

Sacrifice this artifact: Regenerate target artifact.

Mistvault Bridge

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

Tear

Destroy target enchantment.
Fuse (You may cast one or both halves of this card from your hand.)

Wear

Destroy target artifact.
Fuse (You may cast one or both halves of this card from your hand.)

Wear // Tear

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.