Kelsien, the Plague

Vigilance, haste
Kelsien, the Plague gets +1/+1 for each experience counter you have.
{T}: Kelsien deals 1 damage to target creature you don't control. When that creature dies this turn, you get an experience counter.

Lapse of Certainty

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Quietus Spike

Equipped creature has deathtouch.
Whenever equipped creature deals combat damage to a player, that player loses half their life, rounded up.
Equip {3}

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Eater of Virtue

Whenever equipped creature dies, exile it.
Equipped creature gets +2/+0.
As long as a card exiled with Eater of Virtue has flying, equipped creature has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.
Equip {1}

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Gorgon Flail

Equipped creature gets +1/+1 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy that creature.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni, Undying Partisan.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Falthis, Shadowcat Familiar

Commanders you control have menace and deathtouch.
Partner (You can have two commanders if both have partner.)

Drumbellower

Flying
Untap all creatures you control during each other player's untap step.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Kiki-Jiki, Mirror Breaker

Haste
{T}: Create a token that's a copy of target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Maze Abomination

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Multicolored creatures you control have deathtouch.

Augusta, Dean of Order

Other tapped creatures you control get +1/+0.
Other untapped creatures you control get +0/+1.
Whenever you attack, untap each creature you control, then tap any number of creatures you control.

Plargg, Dean of Chaos

{T}, Discard a card: Draw a card.
{4}{R}, {T}: Reveal cards from the top of your library until you reveal a nonlegendary, nonland card with mana value 3 or less. You may cast that card without paying its mana cost. Put all revealed cards not cast this way on the bottom of your library in a random order.

Plargg, Dean of Chaos // Augusta, Dean of Order

Alms Collector

Flash
If an opponent would draw two or more cards, instead you and that player each draw a card.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Magewright's Stone

{1}, {T}: Untap target creature that has an activated ability with {T} in its cost.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your precombat main phase, add {B} for each charge counter on Black Market.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Athreos, Shroud-Veiled

Indestructible
As long as your devotion to white and black is less than seven, Athreos isn't a creature.
At the beginning of your end step, put a coin counter on another target creature.
Whenever a creature with a coin counter on it dies or is put into exile, return that card to the battlefield under your control.

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Boros Charm

Choose one —
• Boros Charm deals 4 damage to target player or planeswalker.
• Permanents you control gain indestructible until end of turn.
• Target creature gains double strike until end of turn.

Haunted Library

Whenever a creature an opponent controls dies, you may pay {1}. If you do, create a 1/1 white Spirit creature token with flying.

Gods Willing

Target creature you control gains protection from the color of your choice until end of turn. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything of that color.)
Scry 1.

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Illusionist's Bracers

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy.
Equip {3}

Damnable Pact

Target player draws X cards and loses X life.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Zagras, Thief of Heartbeats

This spell costs {1} less to cast for each creature in your party.
Flying, deathtouch, haste
Other creatures you control have deathtouch.
Whenever a creature you control deals combat damage to a planeswalker, destroy that planeswalker.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Erase

Ankle Shanker

Haste
Whenever Ankle Shanker attacks, creatures you control gain first strike and deathtouch until end of turn.

Gift of Doom

Enchant creature
Enchanted creature has deathtouch and indestructible.
Morph—Sacrifice another creature. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
As Gift of Doom is turned face up, you may attach it to a creature.

Curse of Vengeance

Enchant player
Whenever enchanted player casts a spell, put a spite counter on Curse of Vengeance.
When enchanted player loses the game, you gain X life and draw X cards, where X is the number of spite counters on Curse of Vengeance.

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.

Giver of Runes

{T}: Another target creature you control gains protection from colorless or from the color of your choice until end of turn.

Vicious Shadows

Whenever a creature dies, you may have Vicious Shadows deal damage to target player equal to the number of cards in that player's hand.

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

General's Enforcer

Legendary Humans you control have indestructible.
{2}{W}{B}: Exile target card from a graveyard. If it was a creature card, create a 1/1 white Human Soldier creature token.

Thornbite Staff

Equipped creature has "{2}, {T}: This creature deals 1 damage to any target" and "Whenever a creature dies, untap this creature."
Whenever a Shaman creature enters the battlefield, you may attach Thornbite Staff to it.
Equip {4}

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

Archetype of Finality

Creatures you control have deathtouch.
Creatures your opponents control lose deathtouch and can't have or gain deathtouch.

Mari, the Killing Quill

Whenever a creature an opponent controls dies, exile it with a hit counter on it.
Assassins, Mercenaries, and Rogues you control have deathtouch and "Whenever this creature deals combat damage to a player, you may remove a hit counter from a card that player owns in exile. If you do, draw a card and create two Treasure tokens."

Ashes of the Abhorrent

Players can't cast spells from graveyards or activate abilities of cards in graveyards.
Whenever a creature dies, you gain 1 life.

Karametra's Blessing

Target creature gets +2/+2 until end of turn. If it's an enchanted creature or enchantment creature, it also gains hexproof and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Go for the Throat

Dreadhound

When Dreadhound enters the battlefield, mill three cards. (Put the top three cards of your library into your graveyard.)
Whenever a creature dies or a creature card is put into a graveyard from a library, each opponent loses 1 life.

Burning Sands

Whenever a creature dies, that creature's controller sacrifices a land.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Mana Tithe

Counter target spell unless its controller pays {1}.

Gorgon's Head

Equipped creature has deathtouch.
Equip {2}

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Staff of Domination

{1}: Untap Staff of Domination.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Battlemage's Bracers

Equipped creature has haste.
Whenever an ability of equipped creature is activated, if it isn't a mana ability, you may pay {1}. If you do, copy that ability. You may choose new targets for the copy.
Equip {2}

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Shadows of the Past

Whenever a creature dies, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)
{4}{B}: Each opponent loses 2 life and you gain 2 life. Activate only if there are four or more creature cards in your graveyard.

Reflection of Kiki-Jiki

{1}, {T}: Create a token that's a copy of another target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Fable of the Mirror-Breaker

(As this Saga enters and after your draw step, add a lore counter.)
I — Create a 2/2 red Goblin Shaman creature token with "Whenever this creature attacks, create a Treasure token."
II — You may discard up to two cards. If you do, draw that many cards.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Fable of the Mirror-Breaker // Reflection of Kiki-Jiki

Darksteel Plate

Indestructible
Equipped creature has indestructible.
Equip {2}

Demonic Tutor

Basilisk Collar

Equipped creature has deathtouch and lifelink.
Equip {2}

Rune of Mortality

Enchant permanent
When Rune of Mortality enters the battlefield, draw a card.
As long as enchanted permanent is a creature, it has deathtouch.
As long as enchanted permanent is an Equipment, it has "Equipped creature has deathtouch."

Vorpal Sword

Equipped creature gets +2/+0 and has deathtouch.
{5}{B}{B}{B}: Until end of turn, Vorpal Sword gains "Whenever equipped creature deals combat damage to a player, that player loses the game."
Equip {B}{B}

Mother of Runes

{T}: Target creature you control gains protection from the color of your choice until end of turn.

Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Aspect of Gorgon

Enchant creature
Enchanted creature gets +1/+3 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy it.)