msem-instigator

First strike
Other Foxes you control get +1/+1.
Whenever a Fox you control becomes blocked, it deals 1 damage to each creature blocking it.

At the beginning of each player's draw step, that player draws two additional cards. At the beginning of their next end step, they discard their hand.

Other creatures have haste and attack each combat if able.
Nonland cards in your hand have paranoia {4}. (The owner of a card with paranoia {4} may cast it from their hand for {4} when a permanent they control leaves the battlefield.)

Prismatic — Whenever you cast a multicolored spell, Thorny Bushwacker has base power and toughness 5/3 until end of turn.

Target creature gets +2/+0 and gains haste until end of turn.
Fabled {2}{R} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Target creature gets +1/+1 until end of turn for each creature you control.
Inscribe {3}{R} ({3}{R}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Untap target creature and gain control of it until end of turn. That creature gains haste until end of turn.

Equipped creature gets +1/+0 and has menace.
Equip {3}

Menace (This creature can't be blocked except by two or more creatures.)

Attacking creatures get +2/+0 until end of turn.
Armed — Equipped creatures you control get an additional +1/+0 until end of turn.

As an additional cost to cast this spell, discard a card.
Draw two cards.

Thunder Wave deals 3 damage to target creature or planeswalker.

Create a 3/3 red Giant creature token with haste.
Creatures you control gain double strike until end of turn.

Vanguard — Whenever a creature you control attacks alone, it gets +1/+1 and gains menace until end of turn.

Flying
Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{R}{R}, {T}: Exile an instant card with mana value 3 or less from your graveyard, then cast a copy of a card exiled with Thunderlash Mystic without paying its mana cost.

Thunderous Applause deals damage to any target equal to the number of tapped creatures you control.

When Thunderstep Ved enters, it deals 1 damage to any target.

Whenever Thunderwolf attacks, exile the top card of your library. You may play that card this turn.

When Timecrafter Lafterii enters, choose target permanent with one or more time counters on it, then put two time counters on it or remove two time counters from it.

When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Prowess
Whenever you cast an instant or sorcery spell, Tirenan Pyromancer deals 1 damage to each opponent.

Enchant creature without flying
Enchanted creature gets +10/+0 and attacks each combat if able.

Until end of turn, target creature gets +1/+0 and gains “Whenever this creature is dealt damage, exile that many cards from the top of your library. Until end of turn, you may play those cards.”

Arm target creature you control. It deals damage equal to its power to any target. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

When Tomb-Raider Duo enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Satrapycycling {2} ({2}, Discard this card: Search your library for a Satrapy card, reveal it, put it into your hand, then shuffle.)