msem-instigator

Reach
When Automated Overwatch enters, create a Function token with “If this spell would create one or more tokens, it creates twice that many of those tokens instead.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Flying, double strike
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Creatures you control get +1/+0 and gain haste until end of turn.

Distribute four +1/+1 counters among up to two target lands you control. Those lands become 0/0 Elemental creatures with haste until end of turn. If you're attacking, tap those lands. They're attacking.
Showcase {3}{R}{G} (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.)

Autumn Ward's power and toughness are each equal to the number of creature cards in your graveyard.
Unveil {2}{B}{G} ({2}{B}{G}: Transform this. Unveil only as a sorcery.)

Choose target creature or planeswalker. Its controller may exile it. If that player doesn't, they sacrifice all other creatures and planeswalkers they control.

{T}, Tap an untapped creature you control: You draw a card and you gain 1 life.

When Autumnal Resonants enters, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Create a 3/3 red and green Elemental creature token with haste.

Sacrifice a creature: Exile the top card of your library. Until end of turn, you may play that card.

Trample
Harmony — Avalanche Drummer deals 1 damage to any target.
When Avalanche Drummer enters, harmonize. (Trigger up to one harmony of a permanent you control.)

{2}: Add one mana of any color.

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)
Blocked creatures you control have first strike.

Flying
Spirited (When this creature enters, you may activate one of its activated abilities without paying its costs.)
{3}{U/B}{U/B}: Look at the top card of target opponent's library, then exile it face down. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast that spell.

{2}: Avaricious Ghul gets +1/+1 until end of turn. If mana from a Treasure was spent to activate this ability, put a +1/+1 counter on Avaricious Ghul instead.

Target creature can't block this turn. (Then exile this card. You may cast the creature later from exile.)

Deathtouch
Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Avatar of Amosis enters, if tribute wasn't paid, you may destroy target creature.

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

Each other colorless creature you control enters with an additional +1/+1 counter on it.

This spell costs {1} less to cast for each artifact and/or enchantment you control.
When Avatar of Innovations enters, you may return target artifact or enchantment card from your graveyard to your hand.

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Crocodile creatures you control get +1/+1.
Avatar of Senmut and Crocodile creatures you control can't be blocked as long as you control four or more Islands.

Vigilance
Avatar of Utsenchep can block any number of creatures.
All creatures able to block Avatar of Utsenchep do so.

Trample
Avatar of the Groves enters with a +1/+1 counter on it for each land you control.
Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Reach, trample
If a +1/+1 counter would be put on another creature you control, instead put a +1/+1 counter on that creature and on Avatar of the Natural.

When Avaz Banner enters, attach it to target creature you control.
Equipped creature gets +2/+2 and is a Soldier Army in addition to its other types.
Equip {3}