msem-instigator

If you would gain life, you gain twice that much life instead.
If you would draw a card, draw two cards instead.
If you tap a permanent for mana, it produces twice as much of that mana instead.

When Twilight Vigil enters, scry 2, then put a night counter on it.
Death knell — Put a night counter on Twilight Vigil. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)
Sacrifice Twilight Vigil: For each night counter on it, you gain 1 life and trigger up to one death knell of a permanent you control.

When Twilight of the Intisuyu enters, draw a card, then choose a card name.
Permanents you control with the chosen name have lifelink and ward {1}.

Each creature you control with a +1/+1 counter on it has double strike.
If one or more +1/+1 counters would be put on a creature you control, put that many plus one +1/+1 counters on that creature instead.

Enchant creature
When Twinklewings enters, draw a card.
Enchanted creature has flying.

Attacking creatures have winnow. (Damage dealt to a creature with winnow also causes its controller to lose that much life.)

Creature tokens you control get +1/+1 and have distorted. (They can be blocked by tapped creatures but not untapped creatures.)

Whenever one or more cards are put into an opponent's graveyard from their hand or library, you may exile the top card of each player's library. Until your next turn, you may cast a card from among those exiled cards and you may spend mana as though it were mana of any type to cast that spell.

At the beginning of your upkeep, exile the top card of your library. You may play it this turn. Whenever you cast an instant or sorcery spell exiled this way, you may copy it and you may choose new targets for the copy.

Double strike
Whenever an Equipment you control enters, create a 3/3 white Archon creature token with flying and attach that Equipment to that token.

I, II — Each opponent loses 2 life and you gain 2 life.
Discovery — At the beginning of your end step, you draw a card and you lose 2 life.

Flying, vigilance
When Tyriel, Angelic Artisan enters, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
Whenever Tyriel attacks, you may put an Equipment card from your hand onto the battlefield, then attach it to Tyriel.

Flash
When Tyrus, Giver to All enters and at the beginning of combat on your turn, for each counter on permanents you control, you may move that counter from that permanent to another permanent you control.

Tzelin of the Demon Realm can't block.
Whenever a Demon you control enters, you may pay {B}. If you do, return Tzelin from your graveyard to the battlefield with a +1/+1 counter on it.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Whenever a Demon you control enters, put a +1/+1 counter on Tzelin.
{2}{B}: Sacrifice Tzelin. If you do, each opponent loses life equal to Tzelin's power. If you're in a renaissance, also draw that many cards.

You may play cards exiled with Azamir planeswalkers.
[+1]: Target player exiles a card from their hand.
[–3]: Exile target nonland permanent unless its controller exiles two other permanents they control.
[–7]: Target opponent may have you take two extra turns after this one. If they don't, you control them during their next turn.

Archive 4 (As this enters, shuffle the top four cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, destroy all nonland permanents you don't control with the same mana value as the drawn card.

Equipped creature gets +2/+2.
Whenever equipped creature attacks, creature spells you cast cost {2} less to cast this turn.
Equip {2}

Whenever Ujuraq, Elder Watcher enters or attacks, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Ujuraq gets +3/+3 and has trample as long as there are eight or more cards in your graveyard.

Other Hounds you control have trample.
{R/W}, {T}: Put a +1/+1 counter on target Hound you control.

Enchant creature
Enchanted creature can't be blocked.
{1}{G}: Enchanted creature gets +1/+1 and gains hexproof until end of turn.

When Unbound Expanse enters, if an opponent controls more lands than you, create a Plains token. (It's a basic land with “{T}: Add {W}.”)
{3}{W}, Sacrifice Unbound Expanse: Exile each nonland permanent you control, then return those cards to the battlefield under your control. Activate only as a sorcery.

Whenever a creature you control is dealt damage, put a +1/+1 counter on that creature.

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.)
Deathtouch

When Uncovered Mine enters and at the beginning of your upkeep, return a random card from your graveyard to your hand.