Huatli, the Sun's Heart

Each creature you control assigns combat damage equal to its toughness rather than its power.
−3: You gain life equal to the greatest toughness among creatures you control.

Gnarled Grovestrider

Vigilance
Other creatures you control have vigilance.

Dormant Grove

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. Then if that creature has toughness 6 or greater, transform this enchantment.

Dormant Grove // Gnarled Grovestrider

Renegade Krasis

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever this creature evolves, put a +1/+1 counter on each other creature you control with a +1/+1 counter on it.

Sharp-Eyed Rookie

Vigilance
Whenever a creature you control enters, if its power is greater than this creature's power or its toughness is greater than this creature's toughness, put a +1/+1 counter on this creature and investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Arwen, Weaver of Hope

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

Cleric Class

(Gain the next level as a sorcery to add its ability.)
If you would gain life, you gain that much life plus 1 instead.
{3}{W}: Level 2
Whenever you gain life, put a +1/+1 counter on target creature you control.
{4}{W}: Level 3
When this Class becomes level 3, return target creature card from your graveyard to the battlefield. You gain life equal to that creature's toughness.

Gluttonous Slug

Menace
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Assault Formation

Each creature you control assigns combat damage equal to its toughness rather than its power.
{G}: Target creature with defender can attack this turn as though it didn't have defender.
{2}{G}: Creatures you control get +0/+1 until end of turn.

Belligerent Brontodon

Each creature you control assigns combat damage equal to its toughness rather than its power.

Treefolk Umbra

Enchant creature
Enchanted creature gets +0/+2 and assigns combat damage equal to its toughness rather than its power.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Watchful Radstag

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever this creature evolves, create a token that's a copy of it.

Rasaad yn Bashir

Each creature you control assigns combat damage equal to its toughness rather than its power.
Whenever Rasaad yn Bashir attacks, if you have the initiative, double the toughness of each creature you control until end of turn.
Choose a Background (You can have a Background as a second commander.)

Experiment One

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Remove two +1/+1 counters from this creature: Regenerate it. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Korozda Guildmage

{1}{B}{G}: Target creature gets +1/+1 and gains intimidate until end of turn. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)
{2}{B}{G}, Sacrifice a nontoken creature: Create X 1/1 green Saproling creature tokens, where X is the sacrificed creature's toughness.

Armored Armadillo

Ward {1} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
{3}{W}: This creature gets +X/+0 until end of turn, where X is its toughness.

Ikra Shidiqi, the Usurper

Menace
Whenever a creature you control deals combat damage to a player, you gain life equal to that creature's toughness.
Partner (You can have two commanders if both have partner.)

Colfenor, the Last Yew

Vigilance, reach
Whenever Colfenor or another creature you control dies, return up to one other target creature card with lesser toughness from your graveyard to your hand.

Momentous Fall

As an additional cost to cast this spell, sacrifice a creature.
You draw cards equal to the sacrificed creature's power, then you gain life equal to its toughness.

Last March of the Ents

This spell can't be countered.
Draw cards equal to the greatest toughness among creatures you control, then put any number of creature cards from your hand onto the battlefield.

Dinosaur Egg

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
When this creature dies, you may discover X, where X is its toughness.

Propagator Drone

Devoid (This card has no color.)
Creature tokens you control have evolve. (They have "Whenever a creature you control enters, if it has greater power or toughness than this token, put a +1/+1 counter on this token." They see this creature enter.)
{3}{G}: Create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

Adipose Offspring

Emerge {5}{W} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When this creature enters, create a 2/2 white Alien creature token. If this creature's emerge cost was paid, instead create X of those tokens, where X is the sacrificed creature's toughness.

Fecund Greenshell

Reach
As long as you control ten or more lands, creatures you control get +2/+2.
Whenever this creature 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.

Doran, the Siege Tower

Each creature assigns combat damage equal to its toughness rather than its power.

Feed the Pack

At the beginning of your end step, you may sacrifice a nontoken creature. If you do, create X 2/2 green Wolf creature tokens, where X is the sacrificed creature's toughness.

Grim Contest

Choose target creature you control and target creature an opponent controls. Each of those creatures deals damage equal to its toughness to the other.

Ancient Lumberknot

Each creature you control with toughness greater than its power assigns combat damage equal to its toughness rather than its power.

Bedrock Tortoise

During your turn, creatures you control have hexproof.
Each creature you control with toughness greater than its power assigns combat damage equal to its toughness rather than its power.

Tree of Redemption

Defender
{T}: Exchange your life total with this creature's toughness.

Gyre Sage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}: Add {G} for each +1/+1 counter on this creature.

Evolving Adaptive

This creature enters with an oil counter on it.
This creature gets +1/+1 for each oil counter on it.
Whenever another creature you control enters, if that creature has greater power or toughness than this creature, put an oil counter on this creature.

Battering Krasis

Trample
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Tree of Perdition

Defender
{T}: Exchange target opponent's life total with this creature's toughness.

Catapult Captain

{2}{B}, {T}, Sacrifice another creature: Target opponent loses life equal to the sacrificed creature's toughness.

Catapult Fodder

At the beginning of combat on your turn, if you control three or more creatures that each have toughness greater than their power, transform this creature.