msem-instigator

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library.
As long as your main library has ten or fewer cards in it, you may cast spells without paying their mana costs.

Choose one —
• Ire of Ancient Tomes deals 2 damage to any target.
• Target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.

{T}: Add {C}.
{T}: Add one mana of any color. You can't spend this to cast spells from your hand.

Create two 1/1 white Soldier creature tokens. Prevent all damage that would be dealt to them this turn.

Deathtouch
When Vision Beyond the Waters enters, each player sacrifices two creatures other than this creature.

Menace (This creature can't be blocked except by two or more creatures.)
When Achet-Aton, Living God enters, if your life total is less than 5, your life total becomes 5.
As long as you have 5 or more life, damage that would reduce your life total to less than 5 reduces it to 5 instead.

Flying
Falkenrath Ordainer has lifelink as long as you control a token.

Enchant player
When Kazimir's Inquisition enters, enchanted player chooses four card names.
Whenever enchanted player casts a spell, if it doesn't have one of the chosen names, enchanted player loses 4 life.

Whenever a -1/-1 counter is put on a creature, you may create a 1/1 green Elf Druid creature token.

When Hideaway Agent enters, gain control of target nonland permanent with mana value 3 or less for as long as you control Hideaway Agent.

Double strike
{3}{R}{W}: Create Hao'Tai's Blessing, a legendary red and white Aura enchantment token with enchant creature and “Enchanted creature gets +3/+3 and has flying” and attach it to Duan, the Fabled Rider.

Vigilance, reach
Tahti, Forged by the World gets +1/+1 for each other creature you control.
Other creatures you control get +1/+1.

Artifact creatures you control get +1/+1.
{1}{U}, Discard an artifact card: Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Deathtouch

Target creature gets +2/+2 for each creature blocking it and gains trample until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Once each turn, when Eruq, the Flamebearer enters or you attack with one or more Horrors, you may have Eruq deal 2 damage to each opponent. Then if Eruq isn't a token, gain control of target creature an opponent controls until end of turn. Tap it. It's attacking its controller.
{2}{R}{R}, Discard Eruq: Create a token that's a copy of Eruq, the Flamebearer, except it's 4/4 and isn't legendary. Activate only as a sorcery.

When Unity Spheres enters, create two 1/1 colorless Construct artifact creature tokens.
Tap two untapped creatures you control: Add two mana of any one color.

Target creature gets -4/-0 until end of turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Warded Tome doesn't untap during your untap step.
{T}: Draw a card.
{5}: Untap Warded Tome.

Whenever Desperate Thief deals combat damage to a player, you may pay 2 life. If you do, draw a card.

Draw a card.
Inscribe {1}{U} ({1}{U}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Flying, lifelink
Whenever Kaalia, Sky's End attacks, it deals 2 damage to any target. It deals an additional 2 damage to that target if you control an Angel. The same is true if you control a Demon. The same is true if you control a Dragon.

Whenever you sacrifice a creature, you may pay {B}{G}. If you do, put a +1/+1 counter on Bloodblade Mercenary and draw a card.

Flying, first strike, haste
Whenever you gain life, you may have Gisela, Blade of Morning deal that much damage to any target. Do this only once each turn.

You may have Shaper of the Formless enter as a copy of any creature on the battlefield, except it has “{2}{U}: Target face-down creature becomes a copy of this creature until end of turn. Turn that creature face up. At the beginning of the next cleanup step, turn it face down.”