msem-instigator

Forgotten Consequences deals 2 damage to target attacking or blocking creature.

({T}: Add {R} or {W}.)
Whenever Forgotten Steppe becomes tapped, you lose 1 life unless you control two or more basic lands.

When Form of the Sunbird enters, it deals 4 damage to each creature. Your life total becomes 4.
If you would lose the game, instead transform Form of the Sunbird.

Fortress Arena enters tapped.
{T}: Add {R} or {W}.
{2}{R}{W}, {T}, Sacrifice Fortress Arena: Draw a card.

{1}{R}{W}: Create a 2/1 red and white Fox creature token. It gains haste. Sacrifice it at the beginning of the next end step.
Whenever Fox of a Brisk Autumn attacks, attacking Foxes you control get +1/+1 until end of turn.

Haste
{W}: Fretport's Heedless gains lifelink until end of turn.
At the beginning of your end step, sacrifice Fretport's Heedless.

({T}: Add {R} or {W}.)
Gnarled Henge enters tapped unless you control two or more basic lands.

Whenever a Hound you control is dealt damage, Greypelt Emissary deals 1 damage to any target.
Whenever Greypelt Emissary attacks, you choose how target creature blocks this combat.

{1}, {T}: Search your library for a card named Greypelt Trooper, reveal it, put it into your hand, then shuffle. Activate only as a sorcery.

[+2]: Up to one target creature must attack Griamoor, Deathless Warrior during its controller's next turn if able.
[0]: Until end of turn, Griamoor becomes a Human Soldier creature with power and toughness each equal to the number of loyalty counters on him and gains indestructible.
[–2]: Griamoor deals damage equal to the number of loyalty counters on him to target creature.

Other creatures you control that are Knights or have Adventures get +1/+1.

Haste
{2}{W}, {T}: Hair-Trigger Marshall deals 2 damage to target blocking creature.

Flying
When Hallowed Executioner enters, it deals 2 damage to each creature without flying.

First mate—Your starting deck contains at least twelve Vehicles. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Haste
{R}{W}, {T}: You may put a Vehicle card from your hand onto the battlefield. That Vehicle gains haste and becomes an artifact creature until end of turn.

Hazy Summits enters tapped.
{T}: Add {R} or {W}.
{1}, {T}: Add one mana of any color.

Enchant creature
Prevent all damage that would be dealt by enchanted creature.
{R}, Sacrifice Heat of Day: It deals 2 damage to enchanted creature.

When Heirloom Seeker enters, you may search your library for an Equipment card, reveal it, then shuffle and put that card on top of it.
Heirloom Seeker has first strike as long as it's equipped.

Flying, lifelink, haste
At the beginning of the end step, sacrifice Helix Entity.

Haste
Herald of Unity's power is equal to the number of creatures you control.

Rapport — Whenever Herald of the Hunt and at least one other creature you control become tapped, nourish 1. (To nourish 1, either put a +1/+1 counter on this creature or create a 1/1 white Citizen creature token.)

When Heroic Aspiration enters, you may search your library for a creature card with an Adventure, reveal it, put it into your hand, then shuffle.
At the beginning of your end step, if you cast both a creature spell and a noncreature spell this turn, Heroic Aspiration deals 2 damage to each opponent and you gain 2 life.

Whenever High-Priestess Nebti attacks or blocks, create a 2/2 white Cat creature token.
{1}{R}{R}, Tap an untapped Cat creature you control: That creature fights target creature you don't control.

When Holy War enters, create three 1/1 white Cleric creature tokens.
Creature tokens you control have first strike and lifelink.

Flying
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Honorable Mentor mentors a creature, that creature and Honorable Mentor each gain first strike until end of turn.