Obosh, the Preypiercer

Companion — Your starting deck contains only cards with odd mana values and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
If a source you control with an odd mana value would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Ferrovore

{R}, Sacrifice an artifact: Ferrovore gets +3/+0 until end of turn.

Incandescent Soulstoke

Other Elemental creatures you control get +1/+1.
{1}{R}, {T}: You may put an Elemental creature card from your hand onto the battlefield. That creature gains haste until end of turn. Sacrifice it at the beginning of the next end step.

Gristleback

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Sacrifice Gristleback: You gain life equal to Gristleback's power.

Lutri, the Spellchaser

Companion — Each nonland card in your starting deck has a different name. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Flash
When Lutri, the Spellchaser enters, if you cast it, copy target instant or sorcery spell you control. You may choose new targets for the copy.

Umori, the Collector

Companion — Each nonland card in your starting deck shares a card type. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
As Umori, the Collector enters, choose a card type.
Spells you cast of the chosen type cost {1} less to cast.

Catalyst Elemental

Sacrifice Catalyst Elemental: Add {R}{R}.

Steppe Glider

Flying, vigilance
{1}{W}: Target creature with a +1/+1 counter on it gains flying and vigilance until end of turn.

Cinder Pyromancer

{T}: Cinder Pyromancer deals 1 damage to target player or planeswalker.
Whenever you cast a red spell, you may untap Cinder Pyromancer.

Crater Elemental

{R}, {T}, Sacrifice Crater Elemental: It deals 4 damage to target creature.
Formidable — {2}{R}: Crater Elemental has base power 8 until end of turn. Activate only if creatures you control have total power 8 or greater.

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.

Swamp

Cytospawn Shambler

Graft 6 (This creature enters with six +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
{G}: Target creature with a +1/+1 counter on it gains trample until end of turn.

Windreaver

Flying
{W}: Windreaver gains vigilance until end of turn.
{W}: Windreaver gets +0/+1 until end of turn.
{U}: Switch Windreaver's power and toughness until end of turn.
{U}: Return Windreaver to its owner's hand.

Cinderbones

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{1}{B}: Regenerate Cinderbones.

Grinning Ignus

{R}, Return Grinning Ignus to its owner's hand: Add {C}{C}{R}. Activate only as a sorcery.

Jungle Creeper

{3}{B}{G}: Return Jungle Creeper from your graveyard to your hand.

Helium Squirter

Graft 3 (This creature enters with three +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
{1}: Target creature with a +1/+1 counter on it gains flying until end of turn.

Molten Ravager

{R}: Molten Ravager gets +1/+0 until end of turn.

Ashiok's Skulker

{3}{U}: Ashiok's Skulker can't be blocked this turn.

Island

Lullmage's Familiar

{T}: Add {G} or {U}.
Whenever you cast a kicked spell, you gain 2 life.

Yorion, Sky Nomad

Companion — Your starting deck contains at least twenty cards more than the minimum deck size. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Flying
When Yorion enters, exile any number of other nonland permanents you own and control. Return those cards to the battlefield at the beginning of the next end step.

Air Servant

Flying
{2}{U}: Tap target creature with flying.

Bloodpyre Elemental

Sacrifice Bloodpyre Elemental: It deals 4 damage to target creature. Activate only as a sorcery.

Vivien's Jaguar

Reach (This creature can block creatures with flying.)
{2}{G}: Return Vivien's Jaguar from your graveyard to your hand. Activate only if you control a Vivien planeswalker.

Plains

Lurking Arynx

Formidable — {2}{G}: Target creature blocks Lurking Arynx this turn if able. Activate only if creatures you control have total power 8 or greater.

Vagrant Plowbeasts

{1}: Regenerate target creature with power 5 or greater.

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.

Forest

Tideforce Elemental

{U}, {T}: You may tap or untap another target creature.
Landfall — Whenever a land you control enters, you may untap Tideforce Elemental.

Rage Nimbus

Defender, flying
{1}{R}: Target creature attacks this turn if able.

Seething Pathblazer

Sacrifice an Elemental: Seething Pathblazer gets +2/+0 and gains first strike until end of turn.

Talonrend

Flying
{U/R}: Talonrend gets +1/-1 until end of turn.

Slaughterhorn

Bloodrush — {G}, Discard Slaughterhorn: Target attacking creature gets +3/+2 until end of turn.

Watercourser

{U}: Watercourser gets +1/-1 until end of turn.

Torrent Elemental

Flying
Whenever Torrent Elemental attacks, tap all creatures defending player controls.
{3}{B/G}{B/G}: Put Torrent Elemental from exile onto the battlefield tapped. Activate only as a sorcery.

Mistwalker

Changeling (This card is every creature type.)
Flying
{1}{U}: Mistwalker gets +1/-1 until end of turn.

Sparkspitter

{R}, {T}, Discard a card: Create a 3/1 red Elemental creature token named Spark Elemental. It has trample, haste, and "At the beginning of the end step, sacrifice Spark Elemental."

Kaheera, the Orphanguard

Companion — Each creature card in your starting deck is a Cat, Elemental, Nightmare, Dinosaur, or Beast card. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Vigilance
Each other creature you control that's a Cat, Elemental, Nightmare, Dinosaur, or Beast gets +1/+1 and has vigilance.

Zirda, the Dawnwaker

Companion — Each permanent card in your starting deck has an activated ability. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Abilities you activate that aren't mana abilities cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.
{1}, {T}: Target creature can't block this turn.

Kranioceros

{1}{W}: Kranioceros gets +0/+3 until end of turn.

Brackwater Elemental

When Brackwater Elemental attacks or blocks, sacrifice it at the beginning of the next end step.
Unearth {2}{U} ({2}{U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Mountain

Cinderhaze Wretch

{T}: Target player discards a card. Activate only during your turn.
Put a -1/-1 counter on Cinderhaze Wretch: Untap Cinderhaze Wretch.

Shore Snapper

{U}: Shore Snapper gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)

Clockwork Vorrac

Trample
Clockwork Vorrac enters with four +1/+1 counters on it.
Whenever Clockwork Vorrac attacks or blocks, remove a +1/+1 counter from it at end of combat.
{T}: Put a +1/+1 counter on Clockwork Vorrac.

Tangle Hulk

Rakeclaw Gargantuan

{1}: Target creature with power 5 or greater gains first strike until end of turn.

Pride Sovereign

Pride Sovereign gets +1/+1 for each other Cat you control.
{W}, {T}, Exert Pride Sovereign: Create two 1/1 white Cat creature tokens with lifelink. (An exerted creature won't untap during your next untap step.)

Leyline Prowler

Deathtouch, lifelink
{T}: Add one mana of any color.

Inner-Flame Igniter

{2}{R}: Creatures you control get +1/+0 until end of turn. If this is the third time this ability has resolved this turn, creatures you control gain first strike until end of turn.

Ridgeline Rager

{R}: Ridgeline Rager gets +1/+0 until end of turn.

Fertilid

Fertilid enters with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from Fertilid: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Keruga, the Macrosage

Companion — Your starting deck contains only cards with mana value 3 or greater and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Keruga, the Macrosage enters, draw a card for each other permanent you control with mana value 3 or greater.