msem-instigator

Look at the top two cards of your library. Put one of them into your hand and the rest into your graveyard.
Rerun (If you cast this from your hand, exile it as it resolves. Whenever a creature you control dies, you may cast this card from exile without paying its mana cost.)

Whenever you cast a spell during an opponent's turn, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

At the beginning of each combat, you may have Elderin, Crystalline Crusader become a copy of another target creature you control with mana value 3 or less until end of turn, except its name is still Elderin, Crystalline Crusader, it's still 3/3, still legendary, and it's an artifact in addition to its other types.
{W}{U}{B}{R}{G}: Elderin gets +3/+3 until end of turn.

Choose two —
• Target player creates two 2/2 white Knight creature tokens with vigilance.
• Destroy target creature with power 4 or greater.
• Target player gains hexproof until end of turn.
• Return target nonland permanent you don't control to its owner's hand.

Whenever a creature dies, its controller loses 1 life.

As Nizev Fortress enters, you may pay 1 life. If you don't, Nizev Fortress enters tapped.
Satrapies you control have “{T}: Add {U}.”

Whenever Imako, Ninefingers becomes tapped, exile the top three cards of target opponent's library face down.
You may look at cards exiled with Imako.
Sacrifice Imako: Turn all cards exiled with it face up. Exile all cards with those names from your opponent's graveyards.

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature deals combat damage to a player, you may aetherize it. (To aetherize, create a token that's a copy of it, then exile that token.)

Trample
Whenever Charging Cassowary deals combat damage to a player, you may cast a copy of an Adventure of a permanent you control.

Flying, vigilance
As Archon of the Accord enters, choose a number.
Spells with mana value equal to the chosen number can't be cast.

Flying, lifelink
When Facsimile of Divinity enters, it deals 4 damage to any target.

{T}: Add {C}.
{T}: Put a +1/+1 counter on each legendary creature and a loyalty counter on each planeswalker that you control entered this turn.

[+1]: Merkurio deals 2 damage to target player or planeswalker. That player or that planeswalker's controller may draw a card.
[–2]: The next instant or sorcery spell you cast this turn costs {U}{R} less to cast. This effect reduces only the amount of colored mana you pay.
[–7]: You get an emblem with “Each instant and sorcery card you own has reverberate {X}, where X is its mana value.” (When you cast a spell, copy it if you paid its reverberate cost. You may choose new targets for the copy.)

{X}, {T}, Sacrifice Macabre Ruins: Target creature gets -X/-X until end of turn.

First strike
Whenever Guardian of the Eclipse attacks, you may exile another target attacking creature you control, then return it to the battlefield under your control tapped and attacking.

Until end of turn, whenever you cast an instant or sorcery spell, you may discard a card. If you do, draw a card.

Prevent all combat damage target creature would deal this turn. You gain life equal to that creature's power.

Scry X, where X is the highest toughness among creatures you control, then reveal the top card of your library. If it's a creature with mana value X or less, you may put it onto the battlefield.

Heretic's Home enters tapped.
{T}: Add {R} or {G}.
When Heretic's Home enters, you may put a loyalty counter on a planeswalker you control.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Spectral Hunter envisions a creature card, creatures you control get +1/+0 until end of turn.

Other Elves you control get +1/+1.
Whenever another Scout you control deals combat damage to a player, you may reveal the top card of your library. If it's a land card, put it onto the battlefield tapped.

Look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order. If you didn't put a card into your hand this way, draw a card.

Haste
At the beginning of combat on your turn, you may have target artifact or enchantment you control become a creature with base power and toughness X/X, where X is its mana value, in addition to its other types and gain haste until end of turn. (If it's attached to a permanent, it becomes unattached.)

{2}{G}: Scarred Brawler gets +2/+2 until end of turn.

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Return each nonland permanent your opponents control to its owner's hand.