Plains

Watcher in the Web

Reach (This creature can block creatures with flying.)
Watcher in the Web can block an additional seven creatures each combat.

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.

Backup Agent

When Backup Agent enters, put a +1/+1 counter on target creature.

Raise the Alarm

Create two 1/1 white Soldier creature tokens.

Enter the Unknown

Target creature you control explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)
You may play an additional land this turn.

Your Temple Is Under Attack

Choose one —
• Pray for Protection — Creatures you control gain indestructible until end of turn.
• Strike a Deal — You and target opponent each draw two cards.

Sandstone Bridge

Sandstone Bridge enters tapped.
When Sandstone Bridge enters, target creature gets +1/+1 and gains vigilance until end of turn.
{T}: Add {W}.

Steadfast Cathar

Whenever Steadfast Cathar attacks, it gets +0/+2 until end of turn.

Stuffed Bear

{2}: Stuffed Bear becomes a 4/4 green Bear artifact creature until end of turn.

Oran-Rief Hydra

Trample
Landfall — Whenever a land you control enters, put a +1/+1 counter on Oran-Rief Hydra. If that land is a Forest, put two +1/+1 counters on Oran-Rief Hydra instead.

Bane of Bala Ged

Whenever Bane of Bala Ged attacks, defending player exiles two permanents they control.

Prophetic Prism

When Prophetic Prism enters, draw a card.
{1}, {T}: Add one mana of any color.

Scrounging Bandar

Scrounging Bandar enters with two +1/+1 counters on it.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Scrounging Bandar onto another target creature.

Unruly Mob

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

Cloud Crusader

Flying
First strike (This creature deals combat damage before creatures without first strike.)

Fencing Ace

Double strike (This creature deals both first-strike and regular combat damage.)

Harvester Troll

When Harvester Troll enters, you may sacrifice a creature or land. If you do, put two +1/+1 counters on Harvester Troll.

Forest

Homestead Courage

Put a +1/+1 counter on target creature you control. It gains vigilance until end of turn.
Flashback {W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Defend the Celestus

Distribute three +1/+1 counters among one, two, or three target creatures you control.

Ethereal Haze

Prevent all damage that would be dealt by creatures this turn.

Timberland Guide

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

Lulu, Loyal Hollyphant

Flying
At the beginning of your end step, if a permanent you controlled left the battlefield this turn, put a +1/+1 counter on each tapped creature you control, then untap them.
Choose a Background (You can have a Background as a second commander.)

Devoted Crop-Mate

You may exert Devoted Crop-Mate as it attacks. When you do, return target creature card with mana value 2 or less from your graveyard to the battlefield. (An exerted creature won't untap during your next untap step.)

Gavony Trapper

Stasis Snare

Flash (You may cast this spell any time you could cast an instant.)
When this enchantment enters, exile target creature an opponent controls until this enchantment leaves the battlefield.

Spear of Heliod

Creatures you control get +1/+1.
{1}{W}{W}, {T}: Destroy target creature that dealt damage to you this turn.

Ruin Processor

When you cast this spell, you may put a card an opponent owns from exile into that player's graveyard. If you do, you gain 5 life.

Seraph of the Suns

Flying
Indestructible (Damage and effects that say "destroy" don't destroy this creature. If its toughness is 0 or less, it's still put into its owner's graveyard.)

Mighty Leap

Target creature gets +2/+2 and gains flying until end of turn.

Tusked Colossodon

Odric's Outrider

Whenever Odric's Outrider or another creature you control dies, put a +1/+1 counter on target creature you control.

Zetalpa, Primal Dawn

Flying, double strike, vigilance, trample, indestructible

Dauntless Survivor

When Dauntless Survivor enters, put a +1/+1 counter on target creature.

Palace Guard

Palace Guard can block any number of creatures.

Battlefront Krushok

Battlefront Krushok can't be blocked by more than one creature.
Each creature you control with a +1/+1 counter on it can't be blocked by more than one creature.

Thornweald Archer

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Gavony Silversmith

When Gavony Silversmith enters, put a +1/+1 counter on each of up to two target creatures.

Darksteel Mutation

Enchant creature
Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.

Broodhunter Wurm

Loxodon Mystic

Shoulder to Shoulder

Support 2. (Put a +1/+1 counter on each of up to two target creatures.)
Draw a card.

Beast Attack

Create a 4/4 green Beast creature token.
Flashback {2}{G}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Inspiring Roar

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

Incremental Growth

Put a +1/+1 counter on target creature, two +1/+1 counters on another target creature, and three +1/+1 counters on a third target creature.

Sigarda, Champion of Light

Flying, trample
Humans you control get +1/+1.
Coven — Whenever Sigarda attacks, if you control three or more creatures with different powers, look at the top five cards of your library. You may reveal a Human creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

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.)

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.

Colossal Dreadmaw

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Eldrazi Devastator

Affa Protector

Cragplate Baloth

Kicker {2}{G}
This spell can't be countered.
Hexproof, haste
If Cragplate Baloth was kicked, it enters with four +1/+1 counters on it.

Vanquish the Horde

This spell costs {1} less to cast for each creature on the battlefield.
Destroy all creatures.

Frontier Mastodon

Ferocious — Frontier Mastodon enters with a +1/+1 counter on it if you control a creature with power 4 or greater.

Strength of the Pack

Put two +1/+1 counters on each creature you control.

Ixalli's Diviner

When Ixalli's Diviner enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Glory Seeker

Shadowbeast Sighting

Create a 4/4 green Beast creature token.
Flashback {6}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Skarrgan Pit-Skulk

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Creatures with power less than Skarrgan Pit-Skulk's power can't block it.

Armorcraft Judge

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

Nissa's Judgment

Support 2. (Put a +1/+1 counter on each of up to two target creatures.)
Choose up to one target creature an opponent controls. Each creature you control with a +1/+1 counter on it deals damage equal to its power to that creature.

Pestilent Wolf

{2}{G}: Pestilent Wolf gains deathtouch until end of turn.

Saddleback Lagac

When Saddleback Lagac enters, support 2. (Put a +1/+1 counter on each of up to two other target creatures.)

Ulamog's Crusher

Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)
Ulamog's Crusher attacks each combat if able.

Druid of the Cowl

Victory's Herald

Flying
Whenever Victory's Herald attacks, attacking creatures gain flying and lifelink until end of turn.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Long Road Home

Exile target creature. At the beginning of the next end step, return that card to the battlefield under its owner's control with a +1/+1 counter on it.