Definitely

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.

Maybe

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Selesnya Signet

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Felidar Retreat

Landfall — Whenever a land you control enters, choose one —
• Create a 2/2 white Cat Beast creature token.
• Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.

Resourceful Defense

Whenever a permanent you control leaves the battlefield, if it had counters on it, put those counters on target permanent you control.
{4}{W}: Move any number of counters from target permanent you control to another target permanent you control.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Thickest in the Thicket

When Thickest in the Thicket enters, put X +1/+1 counters on target creature, where X is that creature's power.
At the beginning of your end step, draw two cards if you control the creature with the greatest power or tied for the greatest power.

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.

Temple Garden

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

Boulderloft Pathway

Branchloft Pathway

Branchloft Pathway // Boulderloft Pathway

Gavony Township

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

Kami of Whispered Hopes

If one or more +1/+1 counters would be put on a permanent you control, that many plus one +1/+1 counters are put on that permanent instead.
{T}: Add X mana of any one color, where X is Kami of Whispered Hopes's power.

Kessig Wolf Run

{T}: Add {C}.
{X}{R}{G}, {T}: Target creature gets +X/+0 and gains trample until end of turn.

Goldvein Hydra

Vigilance, trample, haste
Goldvein Hydra enters with X +1/+1 counters on it.
When Goldvein Hydra dies, create a number of tapped Treasure tokens equal to its power.

Inscription of Abundance

Kicker {2}{G}
Choose one. If this spell was kicked, choose any number instead.
• Put two +1/+1 counters on target creature.
• Target player gains X life, where X is the greatest power among creatures they control.
• Target creature you control fights target creature you don't control.

Basking Broodscale

Devoid (This card has no color.)
{1}{G}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Basking Broodscale, you may create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."

Archdruid's Charm

Choose one —
• Search your library for a creature or land card and reveal it. Put it onto the battlefield tapped if it's a land card. Otherwise, put it into your hand. Then shuffle.
• Put a +1/+1 counter on target creature you control. It deals damage equal to its power to target creature you don't control.
• Exile target artifact or enchantment.

Arcane Signet

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

Restless Bivouac

Restless Bivouac enters tapped.
{T}: Add {R} or {W}.
{1}{R}{W}: Restless Bivouac becomes a 2/2 red and white Ox creature until end of turn. It's still a land.
Whenever Restless Bivouac attacks, put a +1/+1 counter on target creature you control.

Fortified Village

As Fortified Village enters, you may reveal a Forest or Plains card from your hand. If you don't, Fortified Village enters tapped.
{T}: Add {G} or {W}.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Uncivil Unrest

Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)
If a creature you control with a +1/+1 counter on it would deal damage to a permanent or player, it deals double that damage instead.

Llanowar Reborn

Llanowar Reborn enters tapped.
{T}: Add {G}.
Graft 1 (This land enters with a +1/+1 counter on it. Whenever a creature enters, you may move a +1/+1 counter from this land onto it.)

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

Semester's End

Exile any number of target creatures and/or planeswalkers you control. At the beginning of the next end step, return each of them to the battlefield under its owner's control. Each of them enters with an additional +1/+1 counter on it if it's a creature and an additional loyalty counter on it if it's a planeswalker.

Stocking the Pantry

Whenever you put one or more +1/+1 counters on a creature you control, put a supply counter on Stocking the Pantry.
{2}, Remove a supply counter from Stocking the Pantry: Draw a card.

Defiler of Vigor

Trample
As an additional cost to cast green permanent spells, you may pay 2 life. Those spells cost {G} less to cast if you paid life this way. This effect reduces only the amount of green mana you pay.
Whenever you cast a green permanent spell, put a +1/+1 counter on each creature you control.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Invigorating Surge

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

Mossfire Valley

Plains

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Bright-Palm, Soul Awakener

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Whenever this creature attacks, double the number of +1/+1 counters on target creature. That creature can't be blocked by creatures with power 2 or less this turn.

Tribute to the World Tree

Whenever a creature you control enters, draw a card if its power is 3 or greater. Otherwise, put two +1/+1 counters on it.

Court of Garenbrig

When Court of Garenbrig enters, you become the monarch.
At the beginning of your upkeep, distribute two +1/+1 counters among up to two target creatures. Then if you're the monarch, double the number of +1/+1 counters on each creature you control.

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.

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If Incubation Druid has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Evolution Witness

{1}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Whenever one or more +1/+1 counters are put on Evolution Witness, return target permanent card from your graveyard to your hand.

Halana and Alena, Partners

First strike (This creature deals combat damage before creatures without first strike.)
Reach (This creature can block creatures with flying.)
At the beginning of combat on your turn, put X +1/+1 counters on another target creature you control, where X is Halana and Alena's power. That creature gains haste until end of turn.

Gift of the Viper

Put a +1/+1 counter, a reach counter, and a deathtouch counter on target creature. Untap it.

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Thirsting Roots

Choose one —
• Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. Talisman of Impulse deals 1 damage to you.

War Elemental

When War Elemental enters, sacrifice it unless an opponent was dealt damage this turn.
Whenever an opponent is dealt damage, put that many +1/+1 counters on War Elemental.

Good-Fortune Unicorn

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

Brushland

{T}: Add {C}.
{T}: Add {G} or {W}. Brushland deals 1 damage to you.

Innkeeper's Talent

(Gain the next level as a sorcery to add its ability.)
At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
{G}: Level 2
Permanents you control with counters on them have ward {1}.
{3}{G}: Level 3
If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead.

The Red Terror

Advanced Species — Whenever a red source you control deals damage to one or more permanents and/or players, put a +1/+1 counter on The Red Terror.

Bristly Bill, Spine Sower

Landfall — Whenever a land you control enters, put a +1/+1 counter on target creature.
{3}{G}{G}: Double the number of +1/+1 counters on each creature you control.

Drannith Ruins

{T}: Add {C}.
{2}, {T}: Put two +1/+1 counters on target non-Human creature that entered this turn.

Mountain

Hardened Scales

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 it instead.

Biogenic Ooze

When Biogenic Ooze enters, create a 2/2 green Ooze creature token.
At the beginning of your end step, put a +1/+1 counter on each Ooze you control.
{1}{G}{G}{G}: Create a 2/2 green Ooze creature token.

Fangs of Kalonia

Put a +1/+1 counter on target creature you control, then double the number of +1/+1 counters on each creature that had a +1/+1 counter put on it this way.
Overload {4}{G}{G} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Sungrass Prairie

Shalai and Hallar

Flying, vigilance
Whenever one or more +1/+1 counters are put on a creature you control, Shalai and Hallar deals that much damage to target opponent.

Armorcraft Judge

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

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Pledge of Unity

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

Jungle Shrine

Jungle Shrine enters tapped.
{T}: Add {R}, {G}, or {W}.

Vorinclex, Monstrous Raider

Trample, haste
If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead.
If an opponent would put one or more counters on a permanent or player, they put half that many of each of those kinds of counters on that permanent or player instead, rounded down.

Sunpetal Grove

Sunpetal Grove enters tapped unless you control a Forest or a Plains.
{T}: Add {G} or {W}.

Oran-Rief, the Vastwood

Oran-Rief, the Vastwood enters tapped.
{T}: Add {G}.
{T}: Put a +1/+1 counter on each green creature that entered this turn.

Season of Gathering

Choose up to five {P} worth of modes. You may choose the same mode more than once.
{P} — Put a +1/+1 counter on a creature you control. It gains vigilance and trample until end of turn.
{P}{P} — Choose artifact or enchantment. Destroy all permanents of the chosen type.
{P}{P}{P} — Draw cards equal to the greatest power among creatures you control.

Fertilid

Fertilid enters with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from Fertilid: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Mayael's Aria

At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.

Kalonian Hydra

Trample
Kalonian Hydra enters with four +1/+1 counters on it.
Whenever Kalonian Hydra attacks, double the number of +1/+1 counters on each creature you control.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Conclave Sledge-Captain

Backup 1, backup 1, 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. Each backup ability triggers separately.)
Trample
Whenever this creature deals combat damage to a player, put that many +1/+1 counters on it.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Gruul Signet

Annie Joins Up

When Annie Joins Up enters, it deals 5 damage to target creature or planeswalker an opponent controls.
If a triggered ability of a legendary creature you control triggers, that ability triggers an additional time.

Windswept Heath

{T}, Pay 1 life, Sacrifice Windswept Heath: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

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.

Faithful Watchdog

Vigilance
Faithful Watchdog enters with three +1/+1 counters on it.

Communal Brewing

When Communal Brewing enters, any number of target opponents each draw a card. Put an ingredient counter on Communal Brewing, then put an ingredient counter on it for each card drawn this way.
Whenever you cast a creature spell, that creature enters with X additional +1/+1 counters on it, where X is the number of ingredient counters on Communal Brewing.

Silkguard

Put a +1/+1 counter on each of up to X target creatures you control.
Auras, Equipment, and modified creatures you control gain hexproof until end of turn. (Equipment, Auras you control, and counters are modifications.)

Biophagus

Genomic Enhancement — {T}: Add one mana of any color. If this mana is spent to cast a creature spell, that creature enters with an additional +1/+1 counter on it.

Requisition Raid

Spree (Choose one or more additional costs.)
+ {1} — Destroy target artifact.
+ {1} — Destroy target enchantment.
+ {1} — Put a +1/+1 counter on each creature target player controls.

Ozolith, the Shattered Spire

If one or more +1/+1 counters would be put on an artifact or creature you control, that many plus one +1/+1 counters are put on it instead.
{1}{G}, {T}: Put a +1/+1 counter on target artifact or creature you control. Activate only as a sorcery.
Cycling {2} ({2}, Discard this card: Draw a card.)

All Will Be One

Whenever you put one or more counters on a permanent or player, All Will Be One deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.

Shalai, Voice of Plenty

Flying
You, planeswalkers you control, and other creatures you control have hexproof.
{4}{G}{G}: Put a +1/+1 counter on each creature you control.

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.)

Sheltering Landscape

{T}: Add {C}.
{T}, Sacrifice Sheltering Landscape: Search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle.
Cycling {R}{G}{W} ({R}{G}{W}, Discard this card: Draw a card.)

Command Tower

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Sol Ring

Rootbound Crag

Rootbound Crag enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Sunscorch Regent

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Sunscorch Regent and you gain 1 life.

Forest

Temple of Power

(Transforms from Ojer Axonil, Deepest Might.)
{T}: Add {R}.
{2}{R}, {T}: Transform Temple of Power. Activate only if red sources you controlled dealt 4 or more noncombat damage this turn and only as a sorcery.

Ojer Axonil, Deepest Might

Trample
If a red source you control would deal an amount of noncombat damage less than Ojer Axonil's power to an opponent, that source deals damage equal to Ojer Axonil's power instead.
When Ojer Axonil dies, return it to the battlefield tapped and transformed under its owner's control.

Ojer Axonil, Deepest Might // Temple of Power

Arwen, Weaver of Hope

Each other creature you control enters with a number of additional +1/+1 counters on it equal to Arwen, Weaver of Hope's toughness.

Eladamri's Call

Search your library for a creature card, reveal that card, put it into your hand, then shuffle.

The Great Henge

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{T}: Add {G}{G}. You gain 2 life.
Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.