Inkmoth Nexus

{T}: Add {C}.
{1}: Inkmoth Nexus becomes a 1/1 Phyrexian 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.)

Hero of Bladehold

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Whenever Hero of Bladehold attacks, create two 1/1 white Soldier creature tokens that are tapped and attacking.

Etched Champion

Metalcraft — Etched Champion has protection from all colors as long as you control three or more artifacts.

Dispatch

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

Gavony Township

{T}: Add {C}.
{2}{G}{W}, {T}: Put a +1/+1 counter on each creature you control.

Memnite

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Origin Spellbomb

{1}, {T}, Sacrifice Origin Spellbomb: Create a 1/1 colorless Myr artifact creature token.
When Origin Spellbomb is put into a graveyard from the battlefield, you may pay {W}. If you do, draw a card.

Tempered Steel

Artifact creatures you control get +2/+2.

Razorverge Thicket

Razorverge Thicket enters the battlefield tapped unless you control two or fewer other lands.
{T}: Add {G} or {W}.

Signal Pest

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Signal Pest can't be blocked except by creatures with flying or reach.

Glint Hawk

Flying
When Glint Hawk enters the battlefield, sacrifice it unless you return an artifact you control to its owner's hand.

Plains

Glint Hawk Idol

Whenever another artifact enters the battlefield under your control, you may have Glint Hawk Idol become a 2/2 Bird artifact creature with flying until end of turn.
{W}: Glint Hawk Idol becomes a 2/2 Bird artifact creature with flying until end of turn.

Mox Opal

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