msem-instigator

Whenever Sirif of the Lord's Legion attacks, you may put a lore counter on target Saga you control.
Whenever Sirif deals combat damage to a player, you may remove a lore counter from target Saga you control.

Trample
Other creatures you control with trample get +2/+2.
{4}{R}{G}: Put a trample counter on target creature.

Reach
Stonebark Incinerator gets +2/+0 and has trample as long as you control a Dwarf.
Stonebark Incinerator gets +0/+2 and has vigilance as long as you control a Elf.

Vigilance, trample
When Threshold Guardian enters, return a creature you control to its owner's hand.

Trample
Whenever this creature enters or transforms into Valseid, Leyran Brute, it deals 2 damage to any target that isn't a blocking creature and you gain 2 life.
{3}{R}{G}: Transform Valseid, Leyran Brute. Activate only if it's attacking.

When Cryptic Sentinel enters, attach any number of target Auras you control to Cryptic Sentinel.
{G}{W}, Sacrifice an Aura: Tap Cryptic Sentinel. It gains indestructible until end of turn.

Vigilance
Each nontoken creature you control gets +1/+1 for each other creature on the battlefield with the same name as it.

Flying
Other creatures you control enter with an additional +1/+1 counter on them.
If a spell or ability an opponent controls causes you to discard Sigarda, Dawn of Mercy, put it onto the battlefield instead of putting it into your graveyard.

Flash
When Tenvilu, Earthen Warden enters, other creatures you control get +2/+2 and gain hexproof and indestructible until end of turn.

Vigilance
Permanent spells you cast cost {1} less to cast for each 1 damage Tireless Explorer has dealt to players this turn.

Once during each of your turns, you may cast an instant, sorcery, or enchantment spell from your graveyard that targets a creature you control.

If one or more counters would be put on a creature you control, that many plus one of each of those kinds of counters are put on that creature instead.

Flying, vigilance
Whenever Etherwrought Figurehead attacks, you may pay 4 life. If you do, destroy target tapped creature.
If Etherwrought Figurehead would leave the battlefield, exile it instead.

Flying, vigilance, deathtouch, lifelink

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
When Mahara enters, if you cast them, destroy all other creatures.
{W}{B}: Angel — You gain 4 life and amass Soldiers 4. (Put four +1/+1 counters on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)
{5}{W}{B}: Elder — Amass Soldiers 20.

At the beginning of combat on your turn, you may pay 3 life. If you do, target creature seeks secrets or valor. (Give it that Oath Aura. Fulfill secrets by attacking with it and two or more other creatures to draw a card. Fulfill valor by dealing combat damage to a player to create a 2/1 white Soldier token.)
Whenever you fulfill an Oath, each opponent sacrifices a nonland permanent.

Whenever Ser Wayver, the Broken Hour attacks, each opponent loses 2 life and you gain that much life.
When Ser Wayver dies or is countered, exile it with three time counters on it and it gains suspend. (At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast this card without paying its mana cost. It has haste.)

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Whenever a creature enters, its controller sacrifices another creature other than Shan Jun.
{W}{B}: Demigod — Exile each opponent's graveyard. Shan Jun gains protection from each name among cards exiled this way.
{6}{W}{B}: God — Target opponent creates a 1/1 white Avatar creature token with “When this creature dies, you lose the game.”

Tribute 4 (As this creature enters, an opponent of your choice may put four +1/+1 counters on it.)
When Slaughter enters, if tribute was paid, destroy all other creatures. Otherwise, destroy all creatures you don't control.

This spell can't be countered.
Flying
Whenever Ajax, Tyrant of the Empire enters or deals combat damage to a player, draw a card.
Whenever Ajax or another Dragon you control attacks, that Dragon deals 2 damage to any target.

When Emerging Ankulim enters, return each non-Elemental creature to its owner's hand, then Emerging Ankulim deals damage to each player equal to the number of cards in that player's hand.

Flying, haste
Whenever Ma'Long deals combat damage to a player, draw a card, then add that much mana in any combination of {U} and/or {R}. Until end of turn, you don't lose this mana as steps and phases end.
Instant and sorcery cards in your hand have showcase. The showcase cost is equal to the card's mana cost plus {2}. (If you cast it for its showcase cost, create a 1/1 red Bard creature token that can't block and exile that card. Whenever the Bard attacks, you may cast a free copy of the exiled card.)

This spell costs {2} less to cast for each Curse you control.
Flying, vigilance, haste

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Nimble Elemental deals combat damage to a player, you may draw a card. If you do, discard a card.

When Ophidian Oracle enters, draw a card, then abound. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)
Recite {2}{G}{G} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)