msem-instigator

Untap up to two permanents you control during each other player's untap step.

Flying
As long as you control an equipped creature, Guide of Heroes gets +1/+1 and has first strike.
As long as you control an enchanted creature, Guide of Heroes gets +1/+1 and has vigilance.

Flash
Flying
Whenever H13 Wasp enters or you cast an another spell with flash or an instant, exile up to one target nonland permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

[+1]: Haide Bankbuster deals 2 damage divided as you choose among one or two targets.
[+1]: Draw two cards unless any player has Haide Bankbuster deal 3 damage to them.
[–9]: Until end of turn, gain control of all permanents target player controls and they gain haste. Untap those permanents.

Survivors you control have vigilance.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{1}, Sacrifice two Clues: Unlock Hall of Lost Histories and put the revealed card into your hand.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Whenever Haploc Blooddrinker becomes blocked, it gains lifelink until end of turn.

Cast this spell only during your turn and only during the declare attackers step or with its acquiesce ability.
Untap all creatures you control. After this phase, there is an additional combat phase.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Haughty Chateau enters tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

At the beginning of each player's upkeep, sacrifice Hayuan, the Misjudged if that player controls a creature with power 2 or less.
When Hayuan dies, create X Idol tokens, where X is the number of creatures you control. (They're artifacts with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

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

Creature spells you cast cost {1} less to cast.

Flying
If a source without flying would deal damage to you, prevent 2 of that damage.
Crew 5

[+1]: Tap target nonland permanent. It doesn't untap during its controller's next untap step.
[–2]: Exile target tapped nonland permanent.
[–4]: Target player skips their next untap step. Tap up to three target permanents.

[+2]: Until end of turn, Helene Trant becomes a 4/4 Human Warrior creature with hexproof and trample that's still a planeswalker. Prevent all damage that would be dealt to her this turn.
[–2]: Draw two cards.
[–4]: You get an emblem with “Whenever one or more creatures you control deal combat damage to a player, draw a card.”

Hellfire Caverns enters tapped.
{T}: Add {R}.
{2}{R}: Until end of turn, Hellfire Caverns becomes a 3/3 Devil creature with menace. Activate only if you're horrific.

{6}: Until the next time this ability resolves, and as long as Helm of the Infinite and target creature you control are on the battlefield, each other creature is a copy of that creature, and effects that would cause permanents to become creatures cause them to become copies of that creature instead.

Whenever a player casts a noncreature spell, create a 1/1 white Human Soldier creature token.
{1}{U}, Tap four untapped creatures you control: Counter target noncreature spell.

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

Flying, vigilance
At the beginning of your end step, if a creature you control dealt combat damage to an opponent this turn, put a +1/+1 counter on Horizon Prophet.

As Horizon of Origins enters, you may reveal an Island or Mountain card from your hand. If you don't, Horizon of Origins enters tapped.
{T}: Add {U} or {R}.

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

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.)

You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice that creature at the beginning of the next end step.

Destroy target artifact.
Reprise {R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)