msem-instigator

Enchant creature or planeswalker
You control enchanted permanent.
Permanents you control but don't own have hexproof.

Whenever Goreswimmers deals combat damage, put a +1/+1 counter on Goreswimmers.

Creatures you control get +2/+2 and gain trample until end of turn.

Enchant creature
Enchanted creature gets +2/+2.
Sacrifice Steady Reminiscence: Enchanted creature gains indestructible until end of turn.

Once each turn, when Groz, the Nightshaper enters or you attack with one or more Horrors, you may return target nonlegendary creature card from your graveyard to your hand. Then if Groz isn't a token, create a token that's a copy of that creature card.
{2}{B}{B}, Discard Groz: Create a token that's a copy of Groz, the Nightshaper, except it's 4/4 and isn't legendary. Activate only as a sorcery.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Master of Ancient Ways mentors a creature, that creature gains double strike until end of turn.

When Possibility Scope enters, search your library for a land card, exile it, then shuffle.
{T}: Target land you control becomes a copy of a land card exiled with Possibility Scope until end of turn.

Other creatures you control have haste.
Whenever Breach Titan enters or attacks, abound. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)
At the beginning of your end step, return another target creature you control to its owner's hand.

Trample
Assault {2}{R}{G} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Vigilance
Whenever Glittering Narwhal is dealt damage, create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)

When Exergetic Chains enters, exile target nonland permanent you don't control and up to one target creature you control until Exergetic Chains leaves the battlefield.

Deathtouch, protection from legendary
Vielle, Undercity Wayfarer has all loyalty abilities of permanents on the battlefield that cost +1, +0, or -1. (Before cost changes. Add or remove loyalty counters from Vielle to pay their loyalty costs.)

First strike
At the beginning of your end step, each opponent that lost life this turn loses 1 life and discards a card. You gain life equal to the life lost this way, then draw a card for each land card discarded this way.

When Miserable Portent enters, create a 1/1 black Harpy creature token with flying.
{3}{B}, Sacrifice Miserable Portent: You draw two cards and you lose 2 life.

Create three 1/1 red Goblin creature tokens.

Target creature you control gets +1/+1 and gains lifelink until end of turn. It fights target creature you don't control.

[progress 2+]
[progress 5+]
Whenever a creature enters, each opponent loses 1 life.

When Endmire Scourer dies, search your library for a card with mana value 4 or less, reveal it, put it into your hand, then shuffle.

Flash (You may cast this spell any time you could cast an instant.)
When Dazzling Voidmage enters, you may return target attacking creature to its owner's hand.

Abandoned Wilderness enters tapped if you control another nonbasic land.
{T}: Add {G} or {W}.

Enchant creature
Enchanted creature gets +2/+1 and has menace.

Create two 1/1 white Cleric creature tokens with lifelink.

Target creature gets +1/+2 and gains flying until end of turn.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)