msem-instigator

When Horizon Treader enters, exile target enchantment you control, then return that card to the battlefield under your control.

Flying
When Horned Spy enters, look at target player's hand.

Return up to one target permanent card and up to one target Horror card from your graveyard to your hand.

Pressure {3}{B} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Return target creature card from your graveyard to your hand. If this spell was cast for its pressure cost, put that card onto the battlefield instead.

Flying, lifelink

When Host of Nature enters, create two 2/2 red and green Elk creature tokens.

Flying
When Hostile Barbfly enters, you may have it consume. When you do, target creature gets -2/-2 until end of turn. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

This spell costs {3} less to cast if a permanent you controlled advanced this turn.
Gain control of target creature until end of turn. Untap it. It gains haste until end of turn.

Target creature you control gets +2/+0 until end of turn. If that creature is attacking, you may aetherize it. (To aetherize, create a token that's a copy of it, then exile that token.)

{T}: Hotblooded Sorcerer deals 1 damage to target player or planeswalker.
Attain {3}{R} ({3}{R}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever a creature you control becomes renowned, scry 1.

{T}: Target player exiles a card from their graveyard. If they do, you gain 1 life.

Choose one —
• Exile target artifact.
• Target player exiles two artifacts they control with mana value 0.

Flying
When Hoverbike Courier enters, you may reappropriate. If you do, draw a card. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

Hozen Shrine enters tapped.
{T}: Add {U} or {B}.
{U/B}, {T}, Sacrifice Hozen Shrine: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Advance {3}{W} (Cast this for {3}{W} to advance it as it enters. {3}{W}: Advance this as a sorcery.)
Whenever Hrexa Enforcer advances, put a +1/+1 counter on it.

When Humble Archivist enters, you may return target instant or sorcery card from your graveyard to your hand. If you do, conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Humble Fieldhand gets +1/+0 and has vigilance as long as you control an Equipment.

When Humble Tamer enters, create a 1/1 white Griffin creature token with flying.

When Humored Outlaw enters, choose one —
• Put a +1/+1 counter on Humored Outlaw. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)
• Destroy target artifact or enchantment.

Enchant creature
Enchanted creature gets +3/+1 and has haste.

Choose one —
• Destroy target artifact or enchantment.
• Target creature you control deals damage equal to its power to another target creature.

Put a +1/+1 counter on target creature you control. Then that creature fights target creature you don't control. (Each deals damage equal to its power to the other.)

First strike
When Hunted Haunt dies, create a 1/1 black Scout creature token.

Voracious 2 (As this enters, you may sacrifice up to two artifacts and/or creatures. This creature enters with that many +1/+1 counters on it.)
When Hunted Wolf enters, create a 2/2 black Soldier creature token.