msem-instigator

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.)

Cast this spell only if you control a legendary creature or if you control six or more lands.
Exile a planeswalker card you own from outside the game. You may cast that card this 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.

Put a +1/+1 counter on up to one target creature. Untap it. You gain 3 life.

At the beginning of your upkeep, if each opponent controls more lands than you, search your library for a basic land card, reveal it, and put it into your hand, then shuffle.

Flying
{T}, Tap another untapped creature in Heaven's Gale Harrier's pack: Tap target creature. (Two or more creatures you control with equal power are in a pack.)

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Whenever this creature attacks, if it's merged with another card or token, it deals 2 damage to target player or planeswalker.

Enchant creature
Enchanted creature has flying and can only block creatures with flying.

Whenever Hedge Dashers attacks, if you control a permanent with a counter on it, Hedge Dashers gets +1/+1 and gains trample until end of turn.

Rogues and Pirates you control have haste.
Whenever one or more creatures you control deal combat damage to a player, exile the top card of your library. You may play that card this turn.

Untap target creature. It gets +1/+3 until end of turn.

Whenever you lose 2 or more life during your turn, put two blood counters on Hemomancy.
{1}{B}, Remove X blood counters from Hemomancy: Return target creature card with mana value X from your graveyard to the battlefield.

Flying
Herald of Oblivion enters the battlefield with X -1/-1 counters on it, where X is your life total.

Flying
{2}{W}, Sacrifice Herald of the Departed: Create two 1/1 white Spirit creature tokens with flying.

Haste
{1}{R}, {T}: Attacking creatures you control get +1/+0 until end of turn.

Haste
Whenever Herald of the Humble deals combat damage to a player, that player reveals the top card of their library. If it's a nonland card with mana value 3 or less, they may cast it without paying its mana cost.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever a creature deals combat damage to a player, if it was encouraged by Herald of the White Orchid this turn, create a 1/1 white Soldier creature token.

Put a +1/+1 counter on target creature you control. Prevent all damage that would be dealt to that creature this turn.

Beckon Ox {1}{W} ({1}{W}: This enchantment permanently becomes an Ox creature in addition to its other types.)
Vigilance
Whenever a creature or another enchantment enters the battlefield under your control, you gain 1 life.

When Hermetic Fisher dies, you may return target creature to its owner's hand.

Enchant creature or planeswalker
Enchanted permanent has base power 0 and loses all abilities.

Whenever Hero of Aer attacks, it gets +2/+1 until end of turn.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
{T}: Add {G}.
Whenever Hierarch Ranger encourages a creature, add one mana of any color.

Prowess
Whenever High Rollers Croupier attacks, you may put a lore counter on a Saga you control.

Concord — Highland Hermit gets +1/+1 and has hexproof as long as there are four or more card types among permanents you control.