Hardened Scales

If one or more +1/+1 counters would be placed on a creature you control, that many plus one +1/+1 counters are placed on it instead.

Hangarback Walker

Hangarback Walker enters the battlefield with X +1/+1 counters on it. When Hangarback Walker dies, put a 1/1 colorless Thopter artifact creature token with flying onto the battlefield for each +1/+1 counter on Hangarback Walker.{1}, {T}: Put a +1/+1 counter on Hangarback Walker.

Welding Jar

Sacrifice Welding Jar: Regenerate target artifact.

Inkmoth Nexus

{T}: Add {1} to your mana pool. {1}: Inkmoth Nexus becomes a 1/1 Blinkmoth artifact creature with flying and infect until end of turn. It's still a land. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Arcbound Ravager

Sacrifice an artifact: Put a +1/+1 counter on Arcbound Ravager. Modular 1 (This enters the battlefield with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Arcbound Worker

Modular 1 (This enters the battlefield with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Darksteel Citadel

Indestructible (Effects that say "destroy" don't destroy this land.) {T}: Add {1} to your mana pool.

Phyrexia's Core

{T}: Add {1} to your mana pool. {1}, {T}, Sacrifice an artifact: You gain 1 life.

Ancient Stirrings

Look at the top five cards of your library. You may reveal a colorless card from among them and put it into your hand. Then put the rest on the bottom of your library in any order. (Cards with no colored mana in their mana costs are colorless. Lands are also colorless.)

Mox Opal

Metalcraft — {T}: Add one mana of any color to your mana pool. Activate this ability only if you control three or more artifacts.

Throne of Geth

{T}, Sacrifice an artifact: Proliferate. (You choose any number of permanents and/or players with counters on them, then give each another counter of a kind already there.)

Pithing Needle

As Pithing Needle comes into play, name a card. Activated abilities of sources with the chosen name can't be played unless they're mana abilities.

Pendelhaven

{T}: Add {G} to your mana pool. {T}: Target 1/1 creature gets +1/+2 until end of turn.

Llanowar Reborn

Horizon Canopy

Animation Module

Metallic Mimic

Walking Ballista

Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Forest

({T}: Add {G}.)