Ravenous (This creature enters the battlefield with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)

Trample

Heavy Power Hammer — Whenever Aberrant deals combat damage to a player, destroy target artifact or enchantment that player controls.

Balduvian Hydra enters the battlefield with X +1/+0 counters on it.

Remove a +1/+0 counter from Balduvian Hydra: Prevent the next 1 damage that would be dealt to Balduvian Hydra this turn.

: Put a +1/+0 counter on Balduvian Hydra. Activate only during your upkeep.

Benevolent Hydra enters the battlefield with X +1/+1 counters on it.

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

, Remove a +1/+1 counter from Benevolent Hydra: Put a +1/+1 counter on another target creature you control.

Capricopian enters the battlefield with X +1/+1 counters on it.

: Put a +1/+1 counter on Capricopian, then you may reselect which player Capricopian is attacking. Only the player Capricopian is attacking may activate this ability and only during the declare attackers step. (It can't attack its controller.)

Contortionist Troupe enters the battlefield with X +1/+1 counters on it.

Coven — At the beginning of your end step, if you control three or more creatures with different powers, put a +1/+1 counter on target creature you control.

Endless One enters the battlefield with X +1/+1 counters on it.

Feral Hydra enters the battlefield with X +1/+1 counters on it.

: Put a +1/+1 counter on Feral Hydra. Any player may activate this ability.

Vigilance, trample, haste

Goldvein Hydra enters the battlefield with X +1/+1 counters on it.

When Goldvein Hydra dies, create a number of tapped Treasure tokens equal to its power.

Gyrus, Waker of Corpses enters the battlefield with a number of +1/+1 counters on it equal to the amount of mana spent to cast it.

Whenever Gyrus attacks, you may exile target creature card with lesser power from your graveyard. If you do, create a token that's a copy of that card and that's tapped and attacking. Exile the token at end of combat.

Hangarback Walker enters the battlefield with X +1/+1 counters on it.

When Hangarback Walker dies, create a 1/1 colorless Thopter artifact creature token with flying for each +1/+1 counter on Hangarback Walker.

, : Put a +1/+1 counter on Hangarback Walker.

Ravenous (This creature enters the battlefield with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)

Endless Swarm — Whenever a land enters the battlefield under your control, you may pay . If you do, return Hormagaunt Horde from your graveyard to your hand.

As Hydradoodle enters the battlefield, roll X six-sided dice. Hydradoodle enters the battlefield with a number of +1/+1 counters on it equal to the total of those results.

Reach, trample

Skulk (This creature can't be blocked by creatures with greater power.)

Ingenious Prodigy enters the battlefield with X +1/+1 counters on it.

At the beginning of your upkeep, if Ingenious Prodigy has one or more +1/+1 counters on it, you may remove a +1/+1 counter from it. If you do, draw a card.

Knickknack Ouphe enters the battlefield with X +1/+1 counters on it.

When Knickknack Ouphe enters the battlefield, reveal the top X cards of your library. You may put any number of Aura cards with mana value X or less from among them onto the battlefield. Then put all cards revealed this way that weren't put onto the battlefield on the bottom of your library in a random order.

Kurbis, Harvest Celebrant enters the battlefield with a number of +1/+1 counters on it equal to the amount of mana spent to cast it.

Remove a +1/+1 counter from Kurbis: Prevent all damage that would be dealt this turn to another target creature with a +1/+1 counter on it.

Trample, haste

Lightning Serpent enters the battlefield with X +1/+0 counters on it.

At the beginning of the end step, sacrifice Lightning Serpent.

Magma Pummeler enters the battlefield with X +1/+1 counters on it.

If damage would be dealt to Magma Pummeler while it has a +1/+1 counter on it, prevent that damage and remove that many +1/+1 counters from it. When one or more counters are removed from Magma Pummeler this way, it deals that much damage to any target.

Mikaeus, the Lunarch enters the battlefield with X +1/+1 counters on it.

: Put a +1/+1 counter on Mikaeus.

, Remove a +1/+1 counter from Mikaeus: Put a +1/+1 counter on each other creature you control.

Flying

Nimbus Swimmer enters the battlefield with X +1/+1 counters on it.

Omarthis, Ghostfire Initiate enters the battlefield with X +1/+1 counters on it.

Whenever you put one or more +1/+1 counters on another colorless creature, you may put a +1/+1 counter on Omarthis.

When Omarthis dies, manifest a number of cards from the top of your library equal to the number of counters on it.

Primordial Hydra enters the battlefield with X +1/+1 counters on it.

At the beginning of your upkeep, double the number of +1/+1 counters on Primordial Hydra.

Primordial Hydra has trample as long as it has ten or more +1/+1 counters on it.

Vigilance, trample

Rampaging Yao Guai enters the battlefield with X +1/+1 counters on it.

When Rampaging Yao Guai enters the battlefield, destroy any number of target artifacts and/or enchantments with total mana value X or less.

Rock Hydra enters the battlefield with X +1/+1 counters on it.

For each 1 damage that would be dealt to Rock Hydra, if it has a +1/+1 counter on it, remove a +1/+1 counter from it and prevent that 1 damage.

: Prevent the next 1 damage that would be dealt to Rock Hydra this turn.

: Put a +1/+1 counter on Rock Hydra. Activate only during your upkeep.

Defender (This creature can't attack.)

Shifting Wall enters the battlefield with X +1/+1 counters on it.

Ravenous (This creature enters the battlefield with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)

Defender

Spore Chimney — When Sporocyst enters the battlefield, search your library for up to X basic land cards, put them onto the battlefield tapped, then shuffle.

Reach, trample, protection from multicolored

Stonecoil Serpent enters the battlefield with X +1/+1 counters on it.

Ravenous (This creature enters the battlefield with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)

Trample

Spawn Termagants — Whenever Tervigon deals combat damage to a player, create that many 1/1 green Tyranid creature tokens.

Ravenous (This creature enters the battlefield with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)

Shieldwall — Sacrifice Tyrant Guard: Creatures you control with counters on them gain hexproof and indestructible until end of turn.

Vastwood Hydra enters the battlefield with X +1/+1 counters on it.

When Vastwood Hydra dies, you may distribute a number of +1/+1 counters equal to the number of +1/+1 counters on Vastwood Hydra among any number of creatures you control.

Flying

Vrestin enters the battlefield with X +1/+1 counters on it.

When Vrestin enters the battlefield, create X 1/1 green and white Alien Insect creature tokens with flying.

Whenever you attack with one or more Insects, put a +1/+1 counter on each of them.

Wildwood Scourge enters the battlefield with X +1/+1 counters on it.

Whenever one or more +1/+1 counters are put on another non-Hydra creature you control, put a +1/+1 counter on Wildwood Scourge.

Reach

Wren's Run Hydra enters the battlefield with X +1/+1 counters on it.

Reinforce X— (, Discard this card: Put X +1/+1 counters on target creature.)