Plains

Good-Fortune Unicorn

Whenever another creature you control enters, put a +1/+1 counter on that creature.

Abzan Falconer

Outlast {W} ({W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has flying.

Gutter Grime

Whenever a nontoken creature you control dies, put a slime counter on Gutter Grime, then create a green Ooze creature token with "This creature's power and toughness are each equal to the number of slime counters on Gutter Grime."

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Battle for Bretagard

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 1/1 white Human Warrior creature token.
II — Create a 1/1 green Elf Warrior creature token.
III — Choose any number of artifact tokens and/or creature tokens you control with different names. For each of them, create a token that's a copy of it.

Hopeful Initiate

Training (Whenever this creature attacks with another creature with greater power, put a +1/+1 counter on this creature.)
{2}{W}, Remove two +1/+1 counters from among creatures you control: Destroy target artifact or enchantment.

Anafenza, Kin-Tree Spirit

Whenever another nontoken creature you control enters, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Champion of Lambholt

Creatures with power less than Champion of Lambholt's power can't block creatures you control.
Whenever another creature you control enters, put a +1/+1 counter on Champion of Lambholt.

Cazur, Ruthless Stalker

Partner with Ukkima, Stalking Shadow (When this creature enters, target player may put Ukkima into their hand from their library, then shuffle.)
Whenever a creature you control deals combat damage to a player, put a +1/+1 counter on that creature.

Ruinous Intrusion

Exile target artifact or enchantment. Put X +1/+1 counters on target creature you control, where X is the mana value of the permanent exiled this way.

Apprentice Sharpshooter

Reach
Training (Whenever this creature attacks with another creature with greater power, put a +1/+1 counter on this creature.)

Dawnhart Mentor

When Dawnhart Mentor enters, create a 1/1 white Human creature token.
Coven — {5}{G}: Target creature you control gets +3/+3 and gains trample until end of turn. Activate only if you control three or more creatures with different powers.

Settle the Wreckage

Exile all attacking creatures target player controls. That player may search their library for that many basic land cards, put those cards onto the battlefield tapped, then shuffle.

Heronblade Elite

Vigilance
Whenever another Human you control enters, put a +1/+1 counter on Heronblade Elite.
{T}: Add X mana of any one color, where X is Heronblade Elite's power.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Forest

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Pledge of Unity

Put a +1/+1 counter on each creature you control. You gain 1 life for each creature you control.

Garruk's Uprising

When Garruk's Uprising enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample.
Whenever a creature you control with power 4 or greater enters, draw a card.

High Sentinels of Arashin

Flying
High Sentinels of Arashin gets +1/+1 for each other creature you control with a +1/+1 counter on it.
{3}{W}: Put a +1/+1 counter on target creature.

Juniper Order Ranger

Whenever another creature you control enters, put a +1/+1 counter on that creature and a +1/+1 counter on Juniper Order Ranger.

Akroma's Vengeance

Destroy all artifacts, creatures, and enchantments.
Cycling {3} ({3}, Discard this card: Draw a card.)

Hamza, Guardian of Arashin

This spell costs {1} less to cast for each creature you control with a +1/+1 counter on it.
Creature spells you cast cost {1} less to cast for each creature you control with a +1/+1 counter on it.

Dawn

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Return all creature cards with power 2 or less from your graveyard to your hand.

Dusk

Destroy all creatures with power 3 or greater.

Dusk // Dawn

Marwyn, the Nurturer

Whenever another Elf you control enters, put a +1/+1 counter on Marwyn, the Nurturer.
{T}: Add an amount of {G} equal to Marwyn's power.

Arcus Acolyte

Reach, lifelink
Outlast {G/W} ({G/W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each other creature you control without a +1/+1 counter on it has outlast {G/W}.

Duskshell Crawler

When Duskshell Crawler enters, put a +1/+1 counter on target creature.
Each creature you control with a +1/+1 counter on it has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Shamanic Revelation

Draw a card for each creature you control.
Ferocious — You gain 4 life for each creature you control with power 4 or greater.

Dearly Departed

Flying
As long as Dearly Departed is in your graveyard, each Human creature you control enters with an additional +1/+1 counter on it.

Ascendant Acolyte

Ascendant Acolyte enters with a +1/+1 counter on it for each +1/+1 counter among other creatures you control.
At the beginning of your upkeep, double the number of +1/+1 counters on Ascendant Acolyte.

Abzan Battle Priest

Outlast {W} ({W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has lifelink.

Rite of Harmony

Whenever a creature or enchantment you control enters this turn, draw a card.
Flashback {2}{G}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Jiang Yanggu, Wildcrafter

Each creature you control with a +1/+1 counter on it has "{T}: Add one mana of any color."
−1: Put a +1/+1 counter on target creature.

Victory's Envoy

At the beginning of your upkeep, put a +1/+1 counter on each other creature you control.

Druids' Repository

Whenever a creature you control attacks, put a charge counter on Druids' Repository.
Remove a charge counter from Druids' Repository: Add one mana of any color.

End Hostilities

Destroy all creatures and all permanents attached to creatures.

Conclave Mentor

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on that creature instead.
When Conclave Mentor dies, you gain life equal to its power.

Llanowar Elves

Herald of War

Flying
Whenever Herald of War attacks, put a +1/+1 counter on it.
Angel spells and Human spells you cast cost {1} less to cast for each +1/+1 counter on Herald of War.

Cleansing Nova

Choose one —
• Destroy all creatures.
• Destroy all artifacts and enchantments.

Battlefield Promotion

Put a +1/+1 counter on target creature. That creature gains first strike until end of turn. You gain 2 life. (A creature with first strike deals combat damage before creatures without first strike.)

Hamlet Vanguard

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Hamlet Vanguard enters with two +1/+1 counters on it for each other nontoken Human you control.

Enduring Scalelord

Flying
Whenever one or more +1/+1 counters are put on another creature you control, you may put a +1/+1 counter on Enduring Scalelord.

Mace of the Valiant

Equipped creature gets +1/+1 for each charge counter on Mace of the Valiant and has vigilance. (Attacking doesn't cause it to tap.)
Whenever a creature you control enters, put a charge counter on Mace of the Valiant.
Equip {3}

Torens, Fist of the Angels

Training (Whenever this creature attacks with another creature with greater power, put a +1/+1 counter on this creature.)
Whenever you cast a creature spell, create a 1/1 green and white Human Soldier creature token with training.

Gideon's Avenger

Whenever a creature an opponent controls becomes tapped, put a +1/+1 counter on Gideon's Avenger.

Ancient Animus

Put a +1/+1 counter on target creature you control if it's legendary. Then it fights target creature an opponent controls. (Each deals damage equal to its power to the other.)

Cloaked Cadet

Training (Whenever this creature attacks with another creature with greater power, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on one or more Humans you control, draw a card. This ability triggers only once each turn.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Kyler, Sigardian Emissary

Whenever another Human you control enters, put a +1/+1 counter on Kyler, Sigardian Emissary.
Other Humans you control get +1/+1 for each counter on Kyler.

Mentor of the Meek

Whenever another creature you control with power 2 or less enters, you may pay {1}. If you do, draw a card.

Armorcraft Judge

When Armorcraft Judge enters, draw a card for each creature you control with a +1/+1 counter on it.

Savior of Ollenbock

Training (Whenever this creature attacks with another creature with greater power, put a +1/+1 counter on this creature.)
Whenever Savior of Ollenbock trains, exile up to one other target creature from the battlefield or creature card from a graveyard.
When Savior of Ollenbock leaves the battlefield, put the exiled cards onto the battlefield under their owners' control.

Champion of the Parish

Whenever another Human enters under your control, put a +1/+1 counter on Champion of the Parish.

Laid to Rest

Whenever a Human you control dies, draw a card.
Whenever a creature you control with a +1/+1 counter on it dies, you gain 2 life.

Curse of Predation

Enchant player
Whenever a creature attacks enchanted player, put a +1/+1 counter on it.

Angelheart Vial

Whenever you're dealt damage, you may put that many charge counters on Angelheart Vial.
{2}, {T}, Remove four charge counters from Angelheart Vial: You gain 2 life and draw a card.

Cenn's Tactician

{W}, {T}: Put a +1/+1 counter on target Soldier creature.
Each creature you control with a +1/+1 counter on it can block an additional creature each combat.

Bloodspore Thrinax

Devour 1 (As this enters, you may sacrifice any number of creatures. This creature enters with that many +1/+1 counters on it.)
Each other creature you control enters with an additional X +1/+1 counters on it, where X is the number of +1/+1 counters on Bloodspore Thrinax.

Setessan Training

Enchant creature you control
When Setessan Training enters, draw a card.
Enchanted creature gets +1/+0 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.