msem-instigator

If a player would gain life, that player adds that much {C} instead.

Flying
Assault {2}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Harbinger of Locusts assaults, you may search your library for an Insect card, reveal it, put it into your hand, then shuffle.

Hard Bargain deals 2 damage to target creature or planeswalker an opponent controls and you gain 2 life. Then if you have more life than that opponent, draw a card.

Civilized — Hard-Working Oxen gets +3/+0 as long as you control an artifact, a creature, and an enchantment.

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.

Trample
Other Dwarves and Elves you control get +1/+1.
If Harl and Finn or another Dwarf or Elf you control entering the battlefield or attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

As Harlowe, Thespian Extraordinaire enters, choose a color and creature type.
Harlowe, Thespian Extraordinaire is the chosen color.
Harlowe, Thespian Extraordinaire is the chosen type in addition to its other types.

Enchant creature
Enchanted creature gets +2/+2.
Concord — As long as there are four or more card types among permanents you control, enchanted creature has slipstream. (This creature can't be blocked as long as only creatures with slipstream are attacking.)

Choose one —
• Target creature gets +1/+0 and gains indestructible until end of turn.
• Tap target creature. Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
• Scry 1, then draw a card.

Exile the top three cards of your library. When you do, choose one —
• You may play those cards until the end of your next turn.
• Exchange your hand and the exiled cards.

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. Put a +1/+1 counter on each creature you control.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
{3}{G}: Harmonic Recruit gets +2/+2 until end of turn. If you're in a renaissance, it gets +4/+4 until end of turn instead.

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

Draw two cards. Each opponent draws a card.

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

Whenever another nontoken permanent you control enters, create a Food token.
At the beginning of each end step, put X +1/+1 counters on up to one target creature, where X is the amount of life you've gained this turn.

Target creature an opponent controls loses all abilities and has base power and toughness 0/1 until end of turn.
Showcase {4}{U} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

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.

Harpoon Launching deals 3 damage to any target. Create a 1/1 red Goblin creature token.

When Harpooned Bubbledomer enters, mill four cards.
Harpooned Bubbledomer gets +2/+0 and has menace as long as there are four or more card types among cards in your graveyard.

Reach
Whenever one or more creatures with flying attack, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Harpstring Ranger gets +2/+2 until end of turn. Untap it.

{1}, {T}, Move a -1/-1 counter from another creature onto Harried Apothecary: Each opponent loses 1 life and you gain that much life.