Teething Wurmlet

Teething Wurmlet has deathtouch as long as you control three or more artifacts.
Whenever an artifact enters the battlefield under your control, you gain 1 life. If this is the first time this ability has resolved this turn, put a +1/+1 counter on Teething Wurmlet.

Ossification

Enchant basic land you control
When Ossification enters the battlefield, exile target creature or planeswalker an opponent controls until Ossification leaves the battlefield.

Brushland

{T}: Add {C}.
{T}: Add {G} or {W}. Brushland deals 1 damage to you.

Briarbridge Tracker

Vigilance
When Briarbridge Tracker enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
As long as you control a token, Briarbridge Tracker gets +2/+0.

Urza, Prince of Kroog

Artifact creatures you control get +2/+2.
{6}: Create a token that's a copy of target artifact you control, except it's a 1/1 Soldier creature in addition to its other types.

Elvish Archivist

Whenever one or more artifacts enter the battlefield under your control, put two +1/+1 counters on Elvish Archivist. This ability triggers only once each turn.
Whenever one or more enchantments enter the battlefield under your control, draw a card. This ability triggers only once each turn.

Dreamroot Cascade

Dreamroot Cascade enters the battlefield tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Unctus's Retrofitter

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Unctus's Retrofitter enters the battlefield, up to one target artifact you control becomes an artifact creature with base power and toughness 4/4 for as long as Unctus's Retrofitter remains on the battlefield.

Island

Forest

Plains

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

Malcator, Purity Overseer

When Malcator, Purity Overseer enters the battlefield, create a 3/3 colorless Phyrexian Golem artifact creature token.
At the beginning of your end step, if three or more artifacts entered the battlefield under your control this turn, create a 3/3 colorless Phyrexian Golem artifact creature token.

Overgrown Farmland

Overgrown Farmland enters the battlefield tapped unless you control two or more other lands.
{T}: Add {G} or {W}.

Deserted Beach

Deserted Beach enters the battlefield tapped unless you control two or more other lands.
{T}: Add {W} or {U}.

Portrait of Michiko

Portrait of Michiko gets +1/+1 for each artifact and/or enchantment you control.

Michiko's Reign of Truth

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Target creature gets +1/+1 until end of turn for each artifact and/or enchantment you control.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Michiko's Reign of Truth // Portrait of Michiko

Unctus, Grand Metatect

Other blue creatures you control have "Whenever this creature becomes tapped, draw a card, then discard a card."
Other artifact creatures you control get +1/+1.
{U/P}: Until end of turn, target creature you control becomes a blue artifact in addition to its other colors and types. Activate only as a sorcery. ({U/P} can be paid with either {U} or 2 life.)

Yotian Dissident

Whenever an artifact enters the battlefield under your control, put a +1/+1 counter on target creature you control.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Annex Sentry

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Annex Sentry enters the battlefield, exile target artifact or creature an opponent controls with mana value 3 or less until Annex Sentry leaves the battlefield.