Plains

Karametra, God of Harvests

Indestructible
As long as your devotion to green and white is less than seven, Karametra isn't a creature.
Whenever you cast a creature spell, you may search your library for a Forest or Plains card, put it onto the battlefield tapped, then shuffle.

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.

Emiel the Blessed

{3}: Exile another target creature you control, then return it to the battlefield under its owner's control.
Whenever another creature you control enters, you may pay {G/W}. If you do, put a +1/+1 counter on it. If it's a Unicorn, put two +1/+1 counters on it instead. ({G/W} can be paid with either {G} or {W}.)

Splendor Mare

Lifelink
Cycling {1}{W} ({1}{W}, Discard this card: Draw a card.)
When you cycle this card, put a lifelink counter on target creature you control.

Llanowar Elves

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.)

Nissa, Voice of Zendikar

+1: Create a 0/1 green Plant creature token.
−2: Put a +1/+1 counter on each creature you control.
−7: You gain X life and draw X cards, where X is the number of lands you control.

Celestial Unicorn

Whenever you gain life, put a +1/+1 counter on this creature.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Elvish Mystic

Blessed Sanctuary

Prevent all noncombat damage that would be dealt to you and creatures you control.
Whenever a nontoken creature you control enters, create a 2/2 white Unicorn creature token.

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 this creature dies, you gain life equal to its power.

Pridemalkin

When this creature enters, put a +1/+1 counter on target creature you control.
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.)

Make a Stand

Creatures you control get +1/+0 and gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

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.)

Rampant Growth

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

Talisman of Unity

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

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.)

Overrun

Creatures you control get +3/+3 and gain trample until end of turn. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)

Pledge of Unity

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

Zebra Unicorn

Whenever this creature deals damage, you gain that much life.

Lathiel, the Bounteous Dawn

Lifelink
At the beginning of each end step, if you gained life this turn, distribute up to that many +1/+1 counters among any number of other target creatures.

Basri's Solidarity

Put a +1/+1 counter on each creature you control.

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.)

Arcane Signet

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

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Swords to Plowshares

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

Sol Ring

Beast Within

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

Capashen Unicorn

{1}{W}, {T}, Sacrifice this creature: Destroy target artifact or enchantment.

Light of Promise

Enchant creature
Enchanted creature has "Whenever you gain life, put that many +1/+1 counters on this creature."

Opaline Unicorn

Brightmare

When this creature enters, tap up to one target creature. You gain life equal to that creature's power.

Selesnya Signet

Cathars' Crusade

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

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

Ronom Unicorn

Sacrifice this creature: Destroy target enchantment.

Fyndhorn Elves

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.

Generous Gift

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

Wrath of God

Destroy all creatures. They can't be regenerated.

Cleansing Nova

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

Daybreak Charger

When this creature enters, target creature gets +2/+0 until end of turn.

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.

Steadfast Unicorn

{3}{W}: Creatures you control get +1/+1 and gain vigilance until end of turn. Activate only during your turn. (Attacking doesn't cause them to tap.)

Loyal Unicorn

Vigilance
Lieutenant — At the beginning of combat on your turn, if you control your commander, prevent all combat damage that would be dealt to creatures you control this turn. Other creatures you control gain vigilance until end of turn.

Majestic Auricorn

Mutate {3}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Vigilance
Whenever this creature mutates, you gain 4 life.

Wishmonger

{2}: Target creature gains protection from the color of its controller's choice until end of turn. Any player may activate this ability.

Mace of the Valiant

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

Farseek

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

Valorous Steed

Vigilance (Attacking doesn't cause this creature to tap.)
When this creature enters, create a 2/2 white Knight creature token with vigilance.

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Mesa Unicorn

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Forest

Realmwalker

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Good-Fortune Unicorn

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

Irregular Cohort

Changeling (This card is every creature type.)
When this creature enters, create a 2/2 colorless Shapeshifter creature token with changeling.

Harmonize

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Pollenbright Druid

When this creature enters, choose one —
• Put a +1/+1 counter on target creature.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)