msem-instigator

This spell can't be countered.
Whenever Meren, Bane of the Cairns attacks, exile target creature card from your graveyard. You may cast that card for as long as it remains exiled by sacrificing a creature in addition to paying its other costs.

Whenever you attack, you gain 1 life for each attacking creature.
{5}{W}: Put a -1/-1 counter on target tapped creature. This ability costs {X} less to activate, where X is the amount of life you gained this turn.

Attacking creatures you control have “{R}: This creature gets +1/+0 until end of turn.”
Armed — Whenever Forgeborn Barbarian attacks, add {R} for each equipped creature you control.

Copy target spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

When Frontier Savior enters, return up to two target creature cards with mana value 3 or less from your graveyard to the battlefield.

Flash
When Aethermancer's Familiar enters, at the beginning of the next end step, you may aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

[+1]: Discard a card. If you do, up to one target player gains 5 life.
[–3]: Discard a card. You draw X cards and you lose X life, where X is that card's mana value.
[–7]: Exile your hand, then put all cards from your graveyard into your hand and all cards exiled this way into your graveyard.

Bloodprice {2}{B}{B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Return target creature card from your graveyard to your hand. If you cast this spell for its bloodprice, return that card to the battlefield instead.

When Iekin's Portal enters, look at the top five cards of your library. Put one into your hand and the rest into your graveyard.
{1}{U}{U}: Transform Iekin's Portal. Activate only if your fealty to Islands is five or greater.

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever Stalwart Cathar and at least two other creatures attack, Stalwart Cathar gets +2/+0 until end of turn. Untap it.

Search your library for two land cards and reveal them. If you attacked this turn, put them onto the battlefield tapped. Otherwise, put them into your hand. Then shuffle.

Your opponents play with their hands revealed.
Whenever you cast a spell with the same name as a card in an opponent's hand, draw two cards.

Enchant creature
Enchanted creature gets +2/+0 and has first strike.
Mirage {R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Whenever Cruising Schooner attacks, it gets +1/+1 until end of turn.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

Target creature gets +2/+2 and gains first strike until end of turn.
Metamorph {R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

Equipped creature gets +0/+2.
As long as equipped creature is a Wizard, it has “{T}: Scry 1.”
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
At the beginning of your upkeep, create a token that's a copy of the enspirited card. It gains haste until end of turn. Exile it at the beginning of the next end step.

Menace
Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Gilded Sell-Sword gets +2/+0 as long as you're in a renaissance.

{T}: Add {C}.
Whenever you tap Masamori Initiate for mana, you may mill a card.

Exile target creature you control, then return it to the battlefield under its owner's control. Create a token that's a copy of it. Those creatures gain haste until end of turn. Sacrifice the token at the beginning of the next end step.

When Journey to the Zhedina enters, draw a card, then choose a creature card name.
Whenever a creature with the chosen name you control deals damage to a player, put a +1/+1 counter on it.

When Njel Crocodile enters, you may have it fight target creature. (Each deals damage equal to its power to the other.)

Blighted Unicorn can't block.
Ride {3}{B} ({3}{B}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Flying
Whenever a player casts a spell, if it isn't that player's main phase, each of their opponents may draw a card.

Eerie Wildwood enters tapped. When it enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
{T}: Add {R} or {G}.