msem-instigator

Whenever equipped creature attacks, it gets +1/+0 until end of turn for each other attacking creature.
Tap two untapped creatures you control: Equipped creature gains trample until end of turn.
Equip {3}

When Master Chef enters, create a 0/1 green Plant creature token.
Sacrifice a Plant: You gain 3 life.

Whenever an Actor you control becomes untapped, you may discard a card. If you do, draw a card.

Other creatures you control get +0/+1.

Whenever a nonbasic nontoken land enters under an opponent's control, create a tapped colorless land token named Fading Rift with “{T}, Sacrifice this land: Add one mana of any color.”

Whenever an artifact you control enters, Master of Munitions deals 1 damage to each opponent.

Trample
Disgraced 2 (This enters with two -1/-1 counters. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)
Whenever a creature an opponent controls blocks, Master of No Quarter deals 2 damage to that creature.

When Master of the Glen enters, create a 2/2 green Wolf Elemental creature token.
Elementals you control have trample.

When Masterwork Archivist enters, search your library and/or command zone for a legendary card, reveal it, then put it into your hand or graveyard. If you searched your library this way, shuffle.
When Masterwork Archivist dies, you may draw a card.

Equipment spells you cast cost {1} less to cast.
Equip abilities you activate cost {1} less.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | When you next cast an instant or sorcery spell this turn, copy it. You may choose new targets for the copy.
3 | When you cast your next creature spell this turn, copy it.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever one or more creatures you control survive damage, add a quest counter.
You may put a creature card with mana value 2 or less from your hand onto the battlefield.
Put two +1/+1 counters on target creature you control.
Choose target creature you control. You draw cards equal to half that creature's power, rounded down.

Flash
Reach
Whenever Mattia enters or becomes tapped, put a +1/+1 counter on target creature you control.
{2}{G}, {T}: Target creature must be blocked this turn if able. Activate only as a sorcery.

Target creature you control gets +1/+0 until end of turn. It fights up to one target creature you don't control. (Each deals damage equal to its power to the other.)

Poisonous 3 (Whenever this creature deals combat damage to a player, that player gets three poison counters.)
At the beginning of your upkeep, if an opponent is poisoned, you may have Mautakesh Strangler fight target creature you don't control.

As long as you control another white creature, Mavisa's Familar has lifelink. The same is true for blue and flying, black and deathtouch, and red and trample.

[+1]: Untap up to two target creatures and/or lands.
[–2]: Choose a color. Draw cards equal to the number of creatures you control of the chosen color.
[–7]: Reveal the top ten cards of your library. Put all creature and land cards revealed this way onto the battlefield and the rest into your hand.

Reach
When Mawdryk's Harrier enters, look at the top six cards of your library. You may put an Elf card with lesser mana value from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Other Elves you control get +1/+1.

Landfall — Whenever a land you control enters, add {G}.
{3}{G}: Target creature you control gets +2/+2 until end of turn.

When you cast this spell from anywhere other than your hand, it deals 5 damage to any target.
Trample

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)

When Meadow Songstress enters, conjure three cards named Meadow Songstress and shuffle them into your main library.
Whenever a nontoken creature you control enters, if it shares a name with one or more other creatures you control, draw a card.

Enchant creature you control
Whenever enchanted creature attacks, mill three cards.
When enchanted creature leaves the battlefield, create an X/X green Spirit creature token, where X is equal to the number of card types among cards in your graveyard.

Meandering Path enters tapped unless you control one or fewer other lands.
{T}: Add {R} or {G}.
Cycling {2} ({2}, Discard this card: Draw a card.)