msem-instigator

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.)

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.

Heart of Carü Mapu enters tapped.
{T}: Add X mana in any combination of colors, where X is the number of basic land types among lands you control.

At the beginning of your upkeep, create a 1/1 green Saproling creature token.
Whenever a creature you control dies, put a +1/+1 counter on Heart of Spores.
{X}{G}: Move X +1/+1 counters from Heart of Spores onto target creature. Activate only as a sorcery.

{T}: Add {C}.
Wanderlust — {T}: Add one mana of any color. Activate only if you control four or more differently named lands. If you control seven or more, you may add three mana of that color instead.

({T}: Add {G} or {W}.)
Heart of the Glade enters tapped unless you control a basic Forest or a basic Plains.

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.

Gain control of target attacking creature until end of turn. Untap it. It gains indestructible 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.

Bloodprice {U} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Counter target spell unless its controller pays {4}.

Augmented — Whenever you cast a spell from your hand, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, exile cards from the top of your library until you reveal a nonland card with mana value less than that spell's mana value. You may cast that card without paying its mana cost. Put the revealed cards not cast this way on the bottom of your library in a random order.

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

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

Heat Blast deals X damage to target creature or planeswalker.

Heat Ray deals X damage to target creature.

Whenever a creature blocks, Heat of Battle deals 1 damage to that creature's controller.

Enchant creature
Prevent all damage that would be dealt by enchanted creature.
{R}, Sacrifice Heat of Day: It deals 2 damage to enchanted creature.

Until end of turn, gain control of target creature and it gains haste and shimmer. Untap it. (Whenever it attacks this turn, create a tapped and attacking token that's a copy of it. Exile that token at the beginning of the end step.)

Heated Dispute deals 3 damage to any target.
Ferocious — This spell costs {2} less to cast if you control a creature with power 4 or greater.

Shuffle your library, then reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. Heathen Rise deals damage to you equal to the number of cards revealed this way.
Ferocious — That creature gains haste if it has power 4 or greater.

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.

Create a 2/2 white Angel creature token with flying.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Choose a nonland permanent type. Destroy all permanents of the chosen type. Each player who controlled a permanent destroyed this way draws a card.