The Scorpion God

Whenever a creature with a -1/-1 counter on it dies, draw a card.
{1}{B}{R}: Put a -1/-1 counter on another target creature.
When The Scorpion God dies, return it to its owner's hand at the beginning of the next end step.

Yarok, the Desecrated

Deathtouch, lifelink
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Selvala, Heart of the Wilds

Whenever another creature enters, its controller may draw a card if its power is greater than each other creature's power.
{G}, {T}: Add X mana in any combination of colors, where X is the greatest power among creatures you control.

Abigale, Eloquent First-Year

Flying, first strike, lifelink
When Abigale enters, up to one other target creature loses all abilities. Put a flying counter, a first strike counter, and a lifelink counter on that creature.

Grub, Notorious Auntie

Menace
Whenever Grub attacks, you may blight 1. If you do, create a tapped and attacking token that's a copy of the blighted creature, except it has "At the beginning of the end step, sacrifice this token."
At the beginning of your first main phase, you may pay {B}. If you do, transform Grub.

Grub, Storied Matriarch

Menace
Whenever this creature enters or transforms into Grub, Storied Matriarch, return up to one target Goblin card from your graveyard to your hand.
At the beginning of your first main phase, you may pay {R}. If you do, transform Grub.

Grub, Storied Matriarch // Grub, Notorious Auntie

High Perfect Morcant

Whenever High Perfect Morcant or another Elf you control enters, each opponent blights 1. (They each put a -1/-1 counter on a creature they control.)
Tap three untapped Elves you control: Proliferate. Activate only as a sorcery. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Rhys, the Evermore

Flash
When Rhys enters, another target creature you control gains persist until end of turn. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)
{W}, {T}: Remove any number of counters from target creature you control. Activate only as a sorcery.

Mass of Mysteries

First strike, vigilance, trample
At the beginning of combat on your turn, another target Elemental you control gains myriad until end of turn. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Trystan, Penitent Culler

Deathtouch
Whenever this creature transforms into Trystan, Penitent Culler, mill three cards, then you may exile an Elf card from your graveyard. If you do, each opponent loses 2 life.
At the beginning of your first main phase, you may pay {G}. If you do, transform Trystan.

Trystan, Callous Cultivator

Deathtouch
Whenever this creature enters or transforms into Trystan, Callous Cultivator, mill three cards. Then if there is an Elf card in your graveyard, you gain 2 life.
At the beginning of your first main phase, you may pay {B}. If you do, transform Trystan.

Trystan, Callous Cultivator // Trystan, Penitent Culler

Omnath, Locus of Rage

Landfall — Whenever a land you control enters, create a 5/5 red and green Elemental creature token.
Whenever Omnath or another Elemental you control dies, Omnath deals 3 damage to any target.

Glissa Sunslayer

First strike, deathtouch
Whenever Glissa Sunslayer deals combat damage to a player, choose one —
• You draw a card and lose 1 life.
• Destroy target enchantment.
• Remove up to three counters from target permanent.

Ashling, the Limitless

Elemental permanent spells you cast from your hand gain evoke {4} as you cast them. (If you cast a spell for its evoke cost, it's sacrificed when it enters.)
Whenever you sacrifice a nontoken Elemental, create a token that's a copy of it. The token gains haste until end of turn. At the beginning of your next end step, sacrifice it unless you pay {W}{U}{B}{R}{G}.

Hapatra, Vizier of Poisons

Whenever Hapatra deals combat damage to a player, you may put a -1/-1 counter on target creature.
Whenever you put one or more -1/-1 counters on a creature, create a 1/1 green Snake creature token with deathtouch.

Maralen, Fae Ascendant

Flying
Whenever Maralen or another Elf or Faerie you control enters, exile the top two cards of target opponent's library.
Once each turn, you may cast a spell with mana value less than or equal to the number of Elves and Faeries you control from among cards exiled with Maralen this turn without paying its mana cost.

Ashling, Rimebound

Whenever this creature transforms into Ashling, Rimebound and at the beginning of your first main phase, add two mana of any one color. Spend this mana only to cast spells with mana value 4 or greater.
At the beginning of your first main phase, you may pay {R}. If you do, transform Ashling.

Ashling, Rekindled

Whenever this creature enters or transforms into Ashling, Rekindled, you may discard a card. If you do, draw a card.
At the beginning of your first main phase, you may pay {U}. If you do, transform Ashling.

Ashling, Rekindled // Ashling, Rimebound

Muldrotha, the Gravetide

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

Auntie Ool, Cursewretch

Ward—Blight 2. (To blight 2, a player puts two -1/-1 counters on a creature they control.)
Whenever one or more -1/-1 counters are put on a creature, draw a card if you control that creature. If you don't control it, its controller loses 1 life.

Tam, Mindful First-Year

Each other creature you control has hexproof from each of its colors.
{T}: Target creature you control becomes all colors until end of turn.

Kirol, Attentive First-Year

Tap two untapped creatures you control: Copy target triggered ability you control. You may choose new targets for the copy. Activate only once each turn.

Omnath, Locus of the Roil

When Omnath enters, it deals damage to any target equal to the number of Elementals you control.
Landfall — Whenever a land you control enters, put a +1/+1 counter on target Elemental you control. If you control eight or more lands, draw a card.

Isilu, Carrier of Twilight

Flying, lifelink
Each other nontoken creature you control has persist. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)
At the beginning of your first main phase, you may pay {W}. If you do, transform Isilu.

Eirdu, Carrier of Dawn

Flying, lifelink
Creature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a creature spell pays for {1} or one mana of that creature's color.)
At the beginning of your first main phase, you may pay {B}. If you do, transform Eirdu.

Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight

The Reaper, King No More

When The Reaper enters, put a -1/-1 counter on each of up to two target creatures.
Whenever a creature an opponent controls with a -1/-1 counter on it dies, you may put that card onto the battlefield under your control. Do this only once each turn.

Sanar, Innovative First-Year

Vivid — At the beginning of your first main phase, reveal cards from the top of your library until you reveal X nonland cards, where X is the number of colors among permanents you control. For each of those colors, you may exile a card of that color from among the revealed cards. Then shuffle. You may cast the exiled cards this turn.

Brigid, Doun's Mind

{T}: Add X {G} or X {W}, where X is the number of other creatures you control.
At the beginning of your first main phase, you may pay {W}. If you do, transform Brigid.

Brigid, Clachan's Heart

Whenever this creature enters or transforms into Brigid, Clachan's Heart, create a 1/1 green and white Kithkin creature token.
At the beginning of your first main phase, you may pay {G}. If you do, transform Brigid.

Brigid, Clachan's Heart // Brigid, Doun's Mind

Ferrafor, Young Yew

When Ferrafor enters, create a number of 1/1 green Saproling creature tokens equal to the number of counters among creatures target player controls.
{T}: Double the number of each kind of counter on target creature.

Bre of Clan Stoutarm

{1}{W}, {T}: Another target creature you control gains flying and lifelink until end of turn.
At the beginning of your end step, if you gained life this turn, exile cards from the top of your library until you exile a nonland card. You may cast that card without paying its mana cost if the spell's mana value is less than or equal to the amount of life you gained this turn. Otherwise, put it into your hand.

Lluwen, Imperfect Naturalist

When Lluwen enters, mill four cards, then you may put a creature or land card from among the milled cards on top of your library.
{2}{B/G}{B/G}{B/G}, {T}, Discard a land card: Create a 1/1 black and green Worm creature token for each land card in your graveyard.

Sygg, Wanderbrine Shield

Sygg can't be blocked.
Whenever this creature transforms into Sygg, Wanderbrine Shield, target creature you control gains protection from each color until your next turn.
At the beginning of your first main phase, you may pay {U}. If you do, transform Sygg.

Sygg, Wanderwine Wisdom

Sygg can't be blocked.
Whenever this creature enters or transforms into Sygg, Wanderwine Wisdom, target creature gains "Whenever this creature deals combat damage to a player or planeswalker, draw a card" until end of turn.
At the beginning of your first main phase, you may pay {W}. If you do, transform Sygg.

Sygg, Wanderwine Wisdom // Sygg, Wanderbrine Shield

Maelstrom Wanderer

Creatures you control have haste.
Cascade, cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order. Then do it again.)

Massacre Girl, Known Killer

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.

Horde of Notions

Vigilance, trample, haste
{W}{U}{B}{R}{G}: You may play target Elemental card from your graveyard without paying its mana cost.

Doran, Besieged by Time

Each creature spell you cast with toughness greater than its power costs {1} less to cast.
Whenever a creature you control attacks or blocks, it gets +X/+X until end of turn, where X is the difference between its power and toughness.

Jegantha, the Wellspring

Companion — No card in your starting deck has more than one of the same mana symbol in its mana cost. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
{T}: Add {W}{U}{B}{R}{G}. This mana can't be spent to pay generic mana costs.