Plains

Jareth, Leonine Titan

Whenever Jareth, Leonine Titan blocks, it gets +7/+7 until end of turn.
{W}: Jareth gains protection from the color of your choice until end of turn.

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Armored Ascension

Enchant creature
Enchanted creature gets +1/+1 for each Plains you control and has flying.

Entangler

Enchant creature
Enchanted creature can block any number of creatures.

Crawlspace

No more than two creatures can attack you each combat.

Hundred-Handed One

Vigilance
{3}{W}{W}{W}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as Hundred-Handed One is monstrous, it has reach and can block an additional ninety-nine creatures each combat.

Tarrian's Soulcleaver

Equipped creature has vigilance.
Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature.
Equip {2}

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.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Grand Abolisher

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Sun Titan

Vigilance
Whenever Sun Titan enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Stonehewer Giant

Vigilance
{1}{W}, {T}: Search your library for an Equipment card, put it onto the battlefield, attach it to a creature you control, then shuffle.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Slash the Ranks

Destroy all creatures and planeswalkers except for commanders.

Disenchant

Raksha Golden Cub

Vigilance
As long as Raksha Golden Cub is equipped, Cat creatures you control get +2/+2 and have double strike.

Brave the Sands

Creatures you control have vigilance.
Each creature you control can block an additional creature each combat.

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Bastion Protector

Commander creatures you control get +2/+2 and have indestructible.

Silent Arbiter

No more than one creature can attack each combat.
No more than one creature can block each combat.

Kemba, Kha Enduring

Whenever Kemba, Kha Enduring or another Cat you control enters, attach up to one target Equipment you control to that creature.
Equipped creatures you control get +1/+1.
{3}{W}{W}: Create a 2/2 white Cat creature token.

Sword of the Realms

Equipped creature gets +2/+0 and has vigilance.
Whenever equipped creature dies, return it to its owner's hand.
Equip {1}{W}

Halvar, God of Battle

Creatures you control that are enchanted or equipped have double strike.
At the beginning of each combat, you may attach target Aura or Equipment attached to a creature you control to target creature you control.

Halvar, God of Battle // Sword of the Realms

Single Combat

Each player chooses a creature or planeswalker they control, then sacrifices the rest. Players can't cast creature or planeswalker spells until the end of your next turn.

Iona's Blessing

Enchant creature
Enchanted creature gets +2/+2, has vigilance, and can block an additional creature each combat.

Cast Off

Destroy all non-Giant creatures. (Then exile this card. You may cast the creature later from exile.)

Realm-Cloaked Giant

Realm-Cloaked Giant // Cast Off

Vexilus Praetor

Flash
Vigilance
Aegis of the Emperor — Commanders you control have protection from everything.