Urza's Workshop

{T}: Add {C}.
Metalcraft — {T}: Add {C} for each Urza's land you control. Activate only if you control three or more artifacts.

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on this creature.

Wurmcoil Engine

Deathtouch, lifelink
When this creature dies, create a 3/3 colorless Phyrexian Wurm artifact creature token with deathtouch and a 3/3 colorless Phyrexian Wurm artifact creature token with lifelink.

Autonomous Assembler

Prototype {1}{W} — 2/2 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Vigilance
{1}, {T}: Put a +1/+1 counter on target Assembly-Worker you control.

Mine Worker

{T}: You gain 1 life. If you control creatures named Power Plant Worker and Tower Worker, you gain 3 life instead.

Hungering Hydra

This creature enters with X +1/+1 counters on it.
This creature can't be blocked by more than one creature.
Whenever this creature is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)

Mishra's Self-Replicator

Whenever you cast a historic spell, you may pay {1}. If you do, create a token that's a copy of this creature. (Artifacts, legendaries, and Sagas are historic.)

Blossom Dryad

Power Plant Worker

{3}: This creature gets +2/+2 until end of turn. If you control creatures named Mine Worker and Tower Worker, put two +1/+1 counters on this creature instead. Activate only once each turn.

Phyrexian Hydra

Shivan Devastator

Flying, haste
This creature enters with X +1/+1 counters on it.

Crucible of Worlds

Stomping Ground

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Mountain

Hope Tender

{1}, {T}: Untap target land.
{1}, {T}, Exert this creature: Untap two target lands. (An exerted creature won't untap during your next untap step.)

Hydra

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Domesticated Hydra

{X}{G}{G}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
As long as this creature is monstrous, it has trample.

Ill-Tempered Cyclops

Trample
{5}{R}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

Clue

Polukranos, Engine of Ruin

Reach, lifelink
Whenever Polukranos or another nontoken Hydra you control dies, create a 3/3 green and white Phyrexian Hydra creature token with reach and a 3/3 green and white Phyrexian Hydra creature token with lifelink.

Polukranos Reborn

Reach
{6}{W/P}: Transform Polukranos Reborn. Activate only as a sorcery. ({W/P} can be paid with either {W} or 2 life.)

Polukranos Reborn // Polukranos, Engine of Ruin

Forest

Food

{2}, {T}, Sacrifice this token: You gain 3 life.

Wurm

Academy Manufactor

If you would create a Clue, Food, or Treasure token, instead create one of each.

Krosan Restorer

{T}: Untap target land.
Threshold — {T}: Untap up to three target lands. Activate only if seven or more cards are in your graveyard.

Copy

(This token can be used to represent a token that's a copy of a permanent.)

Urza's Factory

{T}: Add {C}.
{7}, {T}: Create a 2/2 colorless Assembly-Worker artifact creature token.

Stone-Seeder Hierophant

Landfall — Whenever a land you control enters, untap this creature.
{T}: Untap target land.

Hydra Broodmaster

{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When this creature becomes monstrous, create X X/X green Hydra creature tokens.

Tower Worker

Reach
{T}: Add {C}. If you control creatures named Mine Worker and Power Plant Worker, add {C}{C}{C} instead.

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

Bootleggers' Stash

Lands you control have "{T}: Create a Treasure token."

Self-Assembler

When this creature enters, you may search your library for an Assembly-Worker creature card, reveal it, put it into your hand, then shuffle.

Treasure

{T}, Sacrifice this token: Add one mana of any color.

Voyaging Satyr

Genesis Hydra

When you cast this spell, reveal the top X cards of your library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield. Then shuffle the rest into your library.
This creature enters with X +1/+1 counters on it.

Gruul Turf

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.