msem-instigator

Flying
Whenever Haunter of the Deadlands attacks, Spirit creatures you control get +1/+1 until end of turn.

{W}, Sacrifice Haunting Bard: Destroy target artifact or enchantment.

Lifelink
Whenever you sacrifice a creature, you gain life equal to its power.

Flying
Whenever Haunting Horseman deals combat damage to a player, that player discards a card.

Enchant creature
Enchanted creature gets -1/-3.

Whenever Haunting Maestro attacks, you may tap or untap up to two target creatures.

Flying, lifelink

Flying
Whenever Havengul Banshee attacks, each creature defending player controls gets -1/-0 until end of turn.
{3}{U}: Return Havengul Banshee from your graveyard to the battlefield transformed under your control attached to target opponent. Activate only as a sorcery.

Scavenge {5}{U} ({5}{U}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Haste (This creature can attack and {T} as soon as it comes under your control.)
Mirage {R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

{T}, Sacrifice Hazy Lagoon: Search your library for a Plains or Island card and put it onto the battlefield tapped, then shuffle.

({T}: Add {U} or {B}.)
Hazy Moorland enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

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

Put target creature on top of its owner's library.
Quickdraw {2}{U} (When a creature you control blocks or becomes blocked, you may cast this spell for {2}{U}.)

Head on Collision deals 2 damage to any target.
Leitmotif (If you cast this spell from your hand, exile it as it resolves. When you next cast a spell that shares a color with this card, you may cast this from exile without paying its mana cost.)

Reach
When Headhunter Mantis enters, if a creature you controlled died this turn, create a 1/1 green Insect creature token.

Flying
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

You gain 5 life, then you may regenerate target creature. (The next time this would be destroyed this turn, it isn't. Instead tap it.)

When Healing Center enters, you gain 2 life.
{T}: Add {C}.

When Healing Potion enters, scry 1, then draw a card.
{2}, {T}, Sacrifice Healing Potion: You gain 4 life.

Menace
Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{R}: Another target creature you control gains menace until end of turn.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{X}{R}: Hearth Dweller gets +X/+0 until end of turn.

Target permanent you control gains hexproof until end of turn. If that permanent is a creature, it also gets +1/+1 until end of turn.

If one or more counters would be put on a creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.

Flying
When Heartless Host enters, arm target creature. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)