msem-instigator

Whenever H.S.S. Demeter becomes blocked by a creature, gain control of that creature.
Whenever H.S.S. Demeter deals combat damage to a player, draw two cards.
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.)

Equipped creature gets +3/+2.
Equip {4}
Hail of Blades's equip ability costs {4} less to activate if it targets an equipped creature.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{1}, Sacrifice two Clues: Unlock Hall of Lost Histories and put the revealed card into your hand.

{T}: Add {C}.
{3}, {T}, Sacrifice Hall of Random Access Memories: Return target artifact, instant, or sorcery card from your graveyard to your hand.

{T}: Add {C}. You gain 1 life.

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if you have a counter.

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.

{2}, {T}: Target opponent exiles a nonland, nontoken permanent they control.
{2}, {T}: Put target permanent card exiled with Harmony Array onto the battlefield under your control.

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.)

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.)

When Haunted Heirloom dies, create a Treasure token.

{T}, Sacrifice Hazy Lagoon: Search your library for a Plains or Island card and put it onto the battlefield tapped, then shuffle.

At the beginning of your end step, exile target permanent.
When Head of Ulko leaves the battlefield, return each other card exiled with it to the battlefield under your control.

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.

{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.

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.

Haste
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

Flying
If a source without flying would deal damage to you, prevent 2 of that damage.
Crew 5

{T}: Add {C}.
When Heavenly Temple enters, target creature gains flying until end of turn.
{2}: Return Heavenly Temple from the battlefield to its owner's hand.

{1}, {T}: Add one mana of any color.
{1}, {T}, Sacrifice Heavy Moneybag: Post a bounty on target creature or planeswalker. Activate only as a sorcery. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

Whenever you cast a noncreature spell, you may put a progress counter on Hellbent Speed.
[PROGRESS 2+] Noncreature spells you cast cost {1} less to cast. This effect can't reduce the amount of mana a spell costs to cast to less than one mana.
[PROGRESS 6+] Whenever you cast a noncreature spell, draw a card.

Equipped creature has hexproof.
Whenever equipped creature dies, draw a card.
Equip {2}

Equipped creature has “{T}: Target attacking creature gets +1/+1 until end of turn.”
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)