msem-instigator

Wanderlust — When you cast this spell, you may copy it if you control four or more differently named lands. You may choose new targets for the copy.
Target creature you don't control gets -3/-3 until end of turn.

When Harvest Blighter enters, create a black Aura Curse enchantment token named Rotting Away attached to target player. The token has enchant player and “Whenever a creature enters under enchanted player's control, if it has toughness 2 or greater, put a -1/-1 counter on that creature.”

Enchant land
Whenever enchanted land is tapped for mana, its controller adds one mana of any color.

When a creature you control scavenges Harvest Reaper, search your library for a colorless card, reveal it, put it into your hand, then shuffle.
Scavenge {4} ({4}, 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.)

Whenever Harvester of Secrets or another creature enters from your graveyard, you may draw a card.
Unearth {2}{U}{B} ({2}{U}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature enters under an opponent's control, you may have that player lose 1 life.

When Hashiro's Vanguard enters, each player sacrifices a nontoken creature.

When Hate-Driven Arsonist enters, you may have it deal X damage to target creature or planeswalker, where X is the number of instant and sorcery cards in your graveyard.

Target player discards two cards and loses 2 life. Scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Reprise {3}{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.)
Hatsuo's Maneuver deals 1 damage to any target. Create a number of 1/1 red Warrior creature tokens equal to the damage dealt by this spell.

Haunted Estate enters tapped unless another player controls a land that could produce {W} or {B}.
{T}: Add {W} or {B}.

{T}: Add {C}.
{T}, Reappropriate: Add {U} or {R}. (Exile exactly two cards from your hand and/or graveyard.)

{T}, Pay 1 life: Add {W} or {U}.
{2}, {T}, Sacrifice Haunted Manor and another permanent: Draw a card. Activate only during your turn.

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

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.

{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.)

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.)

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.

Menace
Sacrifice a Goblin: Heartless Warleader gets +2/+2 until end of turn.

Enchant creature
When Heartstrings leaves the battlefield, exile enchanted creature.
Whenever enchanted creature attacks or blocks, exile it at end of combat.

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

Whenever you attack, you may pay {R}{W}. If you do, create a tapped and attacking token that's a copy of target attacking creature. Sacrifice the token at the beginning of the next end step.