msem-instigator

Double strike
Battalion — Whenever Voracious Howler and at least two other creatures attack, Voracious Howler gets +2/+0 until end of turn.

Reveal cards from the top of your library until three creature and/or land cards are revealed this way. Put all creature and/or land cards revealed this way into your hand and the rest into your graveyard.

Whenever Voracious Spawn enters or attacks, exile up to one target card from a graveyard. If you exile a permanent card, put a +1/+1 counter on Voracious Spawn. If you exile a nonpermanent card, you gain 1 life.

Prowess
{1}{R}: Until end of turn, if an instant, sorcery, or Dragon source you control would deal damage to a permanent or player, it deals that much damage plus 1 to that permanent or player instead. Activate only once each turn.

Equipped creature gets +2/+2.
Whenever equipped creature attacks, exile target nonland permanent defending player controls. For as long as that card remains exiled, its owner may cast it. (They still pay its costs.)
Equip {2}

Reveal the top seven cards of your library. You may put any number of permanent cards with total mana value X or less from among them onto the battlefield, where X is the number of lands you control. Shuffle the rest into your library.

[+1]: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
[–3]: You get an emblem with “{1}{G}: You may play an additional land this turn.”
[–6]: Creatures you control gain trample and have base power and toughness X/X until end of turn, where X is the number of lands you control.

Creatures you control get +0/+1 and have reach.

At the beginning of combat on your turn, create a token that's a copy of another target nonlegendary creature that crewed Voyager's Ark this turn. That token gains haste.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Adorned — As long as Voyaging Devout is equipped and/or enchanted, creatures with power less than its power can't block it.

{T}: Add {C}.
{1}, {T}: Add one mana of any color. When this mana is spent to cast a spell that shares a color with a legendary creature you control, scry 1.

Create a 2/1 red and white Fox creature token. If you're attacking, that token enters tapped and attacking.
Showcase {4}{R} (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.)

WZ-18 Troublemaker enters with a +1/+1 counter on it.
When WZ-18 Troublemaker dies, put its counters on target creature you control.
{1}{R}, Exile WZ-18 Troublemaker from your graveyard: It deals 2 damage to each opponent.

Wake of the Beast deals 2 damage divided as you choose among one or two targets.
Whenever a creature you control becomes monstrous, you may pay {R}. If you do, return Wake of the Beast from your graveyard to your hand.

Prevent all combat damage that would be dealt by non-Spirit creatures this turn.

Search your library for a basic land card or a Forest card, reveal it, and put it into your hand, then shuffle.
Ferocious — Put the revealed card onto the battlefield instead if you control a creature with power 4 or greater.

Walker of the Final Path gets +3/+3 and has trample as long as you control a Horror.
When Walker of the Final Path enters, search your library for a Revelation card, put it into your graveyard, then shuffle.

When Walking Armory enters, return all Equipment cards from your graveyard to the battlefield, then attach them to Walking Armory.

{2}, Sacrifice Walking Platform: Create a 1/1 colorless Thopter artifact creature token with flying.

Play with the top card of your library revealed.
Spells you cast that share a creature type with the top card of your library cost {1} less to cast.

Defender
When Wall of Ivy enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Defender, reach

At the beginning of your end step, draw two cards and you lose 2 life.

Search your library for a Forest or Academy card, put it onto the battlefield tapped, then shuffle.

Ferocious — At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.