msem-instigator

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

When Heirloom Seeker enters, you may search your library for an Equipment card, reveal it, then shuffle and put that card on top of it.
Heirloom Seeker has first strike as long as it's equipped.

Flying, lifelink, haste
At the beginning of the end step, sacrifice Helix Entity.

Haste
Herald of Unity's power is equal to the number of creatures you control.

Rapport — Whenever Herald of the Hunt and at least one other creature you control become tapped, nourish 1. (To nourish 1, either put a +1/+1 counter on this creature or create a 1/1 white Citizen creature token.)

When Heroic Aspiration enters, you may search your library for a creature card with an Adventure, reveal it, put it into your hand, then shuffle.
At the beginning of your end step, if you cast both a creature spell and a noncreature spell this turn, Heroic Aspiration deals 2 damage to each opponent and you gain 2 life.

Whenever High-Priestess Nebti attacks or blocks, create a 2/2 white Cat creature token.
{1}{R}{R}, Tap an untapped Cat creature you control: That creature fights target creature you don't control.

When Holy War enters, create three 1/1 white Cleric creature tokens.
Creature tokens you control have first strike and lifelink.

Flying
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Honorable Mentor mentors a creature, that creature and Honorable Mentor each gain first strike until end of turn.

Humble Bridge enters tapped.
{T}: Add {R} or {W}.
When Humble Bridge enters, you may put a loyalty counter on a planeswalker you control.

Huolin Shrine enters tapped.
{T}: Add {R} or {W}.
{R/W}, {T}, Sacrifice Huolin Shrine: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Once each turn, when you gain life, you may exile the top card of your library. You may play that card this turn.
Whenever you cast your second spell each turn, Ignition Engine deals 2 damage to target player or planeswalker.

As Imperial Barracks enters, you may reveal a Mountain or Plains card from your hand. If you don't, Imperial Barracks enters tapped.
{T}: Add {R} or {W}.

Whenever an opponent casts a spell during your turn or finishes drawing cards during your turn, you gain 1 life and create a Treasure token.
Sacrifice two Treasures: Draw a card.

Whenever Implant Tinkerer or another artifact you control enters, choose one —
• Put a +1/+1 counter on that artifact.
• Implant Tinkerer deals 1 damage to any target and you gain 1 life.

Flying, trample, lifelink

Indestructible
As long as your devotion to red and white is less than seven, Iroas isn't a creature.
Other creatures you control have first strike.
Whenever you attack for the first time each turn, untap all other creatures you control. After this phase, there is an additional combat phase.

({T}: Add {R} or {W}.)
Jagged Crag enters tapped.

Johanna, Skarvith Marshal has first strike as long as it's attacking.
Whenever you attack, you may pay {X}{R/W}{R/W}. When you do, put a +1/+1 counter on each of up to X target attacking creatures. Those creatures gain first strike until end of turn.

If another creature you control would die, exile it instead.
When John Furo, the Unfortunate dies, until your next end step, you may play cards exiled with John Furo.

First strike
Spells can't be cast except during their controller's turns.
Whenever a creature attacks you, Ka Soma deals 1 damage to that creature's controller unless that player pays {1}.

Whenever a creature attacks Kalro, Desert Outpost, it deals 1 damage to that creature.
[+1]: Create a 1/1 red and white Sand Warrior creature token.
[–2]: Destroy target nonbasic land. Its controller creates a colorless Desert land token with “{T}: Add {C}.”

Rhapsody {5}{R}{W} (Pay {5}{R}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Whenever a creature you control with power 4 or greater attacks, look at the top four cards of your library. You may cast a nonland card with mana value 3 or less from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

Improve {R/W} ({R/W}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever an embattled creature you control attacks, you may exile the top card of your library. During any turn you attacked with an embattled creature, you may play that card. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Whenever Lackeybot deals damage to a player, choose an artifact card with mana value X or less at random, where X is the amount of damage dealt. You may create a token that's a copy of that card.