Aragorn, Company Leader

Whenever the Ring tempts you, if you chose a creature other than Aragorn, Company Leader as your Ring-bearer, put your choice of a counter from among first strike, vigilance, deathtouch, and lifelink on Aragorn.
Whenever you put one or more counters on Aragorn, put one of each of those kinds of counters on up to one other target creature.

Chronomaton

{1}, {T}: Put a +1/+1 counter on Chronomaton.

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.)

Needletooth Pack

Morbid — At the beginning of your end step, if a creature died this turn, put two +1/+1 counters on target creature you control.

Explore the Underdark

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.
You take the initiative.

Naturalize

Owlbear Shepherd

At the beginning of your end step, if creatures you control have total power 8 or greater, draw a card.

Somberwald Spider

Reach (This creature can block creatures with flying.)
Morbid — Somberwald Spider enters with two +1/+1 counters on it if a creature died this turn.

Blossoming Sands

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {W}.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Master Chef

Commander creatures you own have "This creature enters with an additional +1/+1 counter on it" and "Other creatures you control enter with an additional +1/+1 counter on them."

Armasaur Guide

Vigilance (Attacking doesn't cause this creature to tap.)
Whenever you attack with three or more creatures, put a +1/+1 counter on target creature you control.

Plains

Quirion Beastcaller

Whenever you cast a creature spell, put a +1/+1 counter on Quirion Beastcaller.
When Quirion Beastcaller dies, distribute X +1/+1 counters among any number of target creatures you control, where X is the number of +1/+1 counters on Quirion Beastcaller.

Forest

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Oran-Rief Ooze

When Oran-Rief Ooze enters, put a +1/+1 counter on target creature you control.
Whenever Oran-Rief Ooze attacks, put a +1/+1 counter on each attacking creature with a +1/+1 counter on it.

Stony Strength

Put a +1/+1 counter on target creature you control. Untap that creature.

Spined Tyrranax

At the beginning of combat on your turn, you may pay {2}{G}. When you do, put a +1/+1 counter on target creature. That creature gains trample until end of turn. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Common Bond

Put a +1/+1 counter on target creature.
Put a +1/+1 counter on target creature.

Aggressive Instinct

Target creature you control deals damage equal to its power to target creature you don't control.

Ring of Thune

Equipped creature has vigilance. (Attacking doesn't cause it to tap.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's white.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Serra Redeemer

Flying
Whenever another creature you control with power 2 or less enters, put two +1/+1 counters on that creature.

Revive

Return target green card from your graveyard to your hand.

Dusk Legion Duelist

Vigilance
Whenever one or more +1/+1 counters are put on Dusk Legion Duelist, draw a card. This ability triggers only once each turn.

Horizon Spellbomb

{2}, {T}, Sacrifice Horizon Spellbomb: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
When Horizon Spellbomb is put into a graveyard from the battlefield, you may pay {G}. If you do, draw a card.

Howlgeist

Creatures with power less than Howlgeist's power can't block it.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Celebrity Fencer

Alliance — Whenever another creature you control enters, put a +1/+1 counter on Celebrity Fencer.

Storm the Seedcore

Distribute four +1/+1 counters among up to four target creatures you control. Creatures you control gain vigilance and trample until end of turn.

Apex Hawks

Multikicker {1}{W} (You may pay an additional {1}{W} any number of times as you cast this spell.)
Flying
Apex Hawks enters with a +1/+1 counter on it for each time it was kicked.

Travel Preparations

Put a +1/+1 counter on each of up to two target creatures.
Flashback {1}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Timberland Guide

When Timberland Guide enters, put a +1/+1 counter on target creature.

Pileated Provisioner

Flying
When Pileated Provisioner enters, put a +1/+1 counter on target creature you control without flying.

Ring of Kalonia

Equipped creature has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's green.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Lae'zel, Vlaakith's Champion

If you would put one or more counters on a creature or planeswalker you control or on yourself, put that many plus one of each of those kinds of counters on that permanent or player instead.
Choose a Background (You can have a Background as a second commander.)

Sejiri Steppe

Sejiri Steppe enters tapped.
When Sejiri Steppe enters, target creature you control gains protection from the color of your choice until end of turn.
{T}: Add {W}.

Noble Heritage

Commander creatures you own have "When this creature enters and at the beginning of your upkeep, each player may put two +1/+1 counters on a creature they control. For each opponent who does, you gain protection from that player until your next turn." (You can't be targeted, dealt damage, or enchanted by anything controlled by that player.)

Raise the Past

Return all creature cards with mana value 2 or less from your graveyard to the battlefield.

Siege Veteran

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
Whenever another nontoken Soldier you control dies, create a 1/1 colorless Soldier artifact creature token.

Greenwood Sentinel

Vigilance (Attacking doesn't cause this creature to tap.)

Ent-Draught Basin

{X}, {T}: Put a +1/+1 counter on target creature with power X. Activate only as a sorcery.

Withstand Death

Target creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it. If its toughness is 0 or less, it's still put into its owner's graveyard.)

Feral Contest

Put a +1/+1 counter on target creature you control. Another target creature blocks it this turn if able.

Sol Ring

You Meet in a Tavern

Choose one —
• Form a Party — Look at the top five cards of your library. You may reveal any number of creature cards from among them and put them into your hand. Put the rest on the bottom of your library in a random order.
• Start a Brawl — Creatures you control get +2/+2 until end of turn.

Zar Ojanen, Scion of Efrava

Domain — Whenever Zar Ojanen, Scion of Efrava becomes tapped, put a +1/+1 counter on each creature you control with toughness less than the number of basic land types among lands you control.

Fairgrounds Trumpeter

At the beginning of each end step, if a +1/+1 counter was put on a permanent under your control this turn, put a +1/+1 counter on Fairgrounds Trumpeter.

Ascendant Packleader

Ascendant Packleader enters with a +1/+1 counter on it if you control a permanent with mana value 4 or greater.
Whenever you cast a spell with mana value 4 or greater, put a +1/+1 counter on Ascendant Packleader.

Etched Cornfield

Etched Cornfield enters tapped unless a player has 13 or less life.
{T}: Add {G} or {W}.

Finneas, Ace Archer

Vigilance, reach
Whenever Finneas, Ace Archer attacks, put a +1/+1 counter on each other creature you control that's a token or a Rabbit. Then if creatures you control have total power 10 or greater, draw a card.

Boon-Bringer Valkyrie

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following abilities until end of turn.)
Flying, first strike, lifelink

Galadriel, Gift-Giver

Whenever Galadriel, Gift-Giver enters or attacks, choose one —
• Put a +1/+1 counter on another target creature.
• Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
• Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Invigorating Surge

Put a +1/+1 counter on target creature you control, then double the number of +1/+1 counters on that creature.

Take Up the Shield

Put a +1/+1 counter on target creature. It gains lifelink and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Fecund Greenshell

Reach
As long as you control ten or more lands, creatures you control get +2/+2.
Whenever Fecund Greenshell or another creature you control with toughness greater than its power enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. Otherwise, put it into your hand.

Prey Upon

Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)

Flourishing Hunter

When Flourishing Hunter enters, you gain life equal to the greatest toughness among other creatures you control.

Stone of Erech

If a creature an opponent controls would die, exile it instead.
{2}, {T}, Sacrifice Stone of Erech: Exile target player's graveyard. Draw a card.

Deepwood Denizen

Vigilance (Attacking doesn't cause this creature to tap.)
{5}{G}, {T}: Draw a card. This ability costs {1} less to activate for each +1/+1 counter on creatures you control.

Byrke, Long Ear of the Law

Vigilance
When Byrke, Long Ear of the Law enters, put a +1/+1 counter on each of up to two target creatures.
Whenever a creature you control with a +1/+1 counter on it attacks, double the number of +1/+1 counters on it.

Aragorn and Arwen, Wed

Vigilance
Whenever Aragorn and Arwen, Wed enters or attacks, put a +1/+1 counter on each other creature you control. You gain 1 life for each other creature you control.

Rabid Bite

Band Together

Up to two target creatures you control each deal damage equal to their power to another target creature.

Many Partings

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Graypelt Refuge

Graypelt Refuge enters tapped.
When Graypelt Refuge enters, you gain 1 life.
{T}: Add {G} or {W}.

Gnoll Hunter

Pack tactics — Whenever Gnoll Hunter attacks, if you attacked with creatures with total power 6 or greater this combat, put a +1/+1 counter on Gnoll Hunter.

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.

Wing Puncture

Target creature you control deals damage equal to its power to target creature with flying.

Unruly Mob

Whenever another creature you control dies, put a +1/+1 counter on Unruly Mob.

Andúril, Narsil Reforged

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Whenever equipped creature attacks, put a +1/+1 counter on each creature you control. If you have the city's blessing, put two +1/+1 counters on each creature you control instead.
Equip {3}

Hunger of the Howlpack

Put a +1/+1 counter on target creature.
Morbid — Put three +1/+1 counters on that creature instead if a creature died this turn.

Gnarlid Pack

Multikicker {1}{G} (You may pay an additional {1}{G} any number of times as you cast this spell.)
Gnarlid Pack enters with a +1/+1 counter on it for each time it was kicked.

Good-Fortune Unicorn

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

Graypelt Hunter

Trample
Whenever Graypelt Hunter or another Ally you control enters, you may put a +1/+1 counter on Graypelt Hunter.

Repel Calamity

Destroy target creature with power or toughness 4 or greater.

Ajani, the Greathearted

Creatures you control have vigilance.
+1: You gain 3 life.
−2: Put a +1/+1 counter on each creature you control and a loyalty counter on each other planeswalker you control.