msem-instigator

When Hand of Fury enters, it gets +2/+2 and gains haste until end of turn.
At the beginning of your upkeep, if your fealty to Mountains is five or greater, transform Hand of Fury. (Each Mountain you control counts towards your fealty to Mountains.)

When Hand of the Evil One enters, mill three cards. Draw a card for each Zombie card milled this way.
Unearth abilities you activate cost up to {1} less to activate.

Menace (This creature can't be blocked except by two or more creatures.)
Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{U}, {T}: You may tap or untap target Human.

Trample
At the beginning of your upkeep, if your fealty to Forests is five or greater, transform Hand of the Harvest. (Each Forest you control counts towards your fealty to Forests.)

Hanweir Miscreant can't be blocked by creature tokens.
{2}{R}: Transform Hanweir Miscreant. Activate only if it's attacking.

Whenever one or more Rogues you control attack, you may pay 1 life. If you do, draw a card.

Lifelink
{2}{B}: Target Spirit gets +1/+0 and gains lifelink until end of turn.

When Hardlight Visionary enters, create a Function token with “Until end of turn, target creature becomes a 5/5 Dragon and gains flying.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Trample
As an additional cost to cast creature spells, you may sacrifice a permanent. If you do, that spell costs {2} less to cast and that creature enters with an additional +1/+1 counter on it.

The next 2 damage that a source of your choice would deal to you and/or permanents you control this turn is dealt to any target instead.

Whenever you cast an enchantment spell, you may pay {W}. If you do, put a +1/+1 counter on target creature.

Tap any number of untapped creatures you control. You gain 4 life for each creature tapped this way.

First strike
Whenever you discard a card, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Ferocious — Whenever a creature with power 4 or greater you control enters, you gain 4 life.

When Harried Submersible enters, target opponent creates a 1/1 blue Tentacle creature token.
Whenever Harried Submersible deals combat damage to a player or planeswalker, draw a card.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

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.)

Reach, trample
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever one or more tokens you control enter, put a +1/+1 counter on Harvesttide Nemesis. This ability triggers only once each turn.

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.