Arvinox, the Mind Flail isn't a creature unless you control three or more permanents you don't own.

At the beginning of your end step, exile the bottom card of each opponent's library face down. For as long as those cards remain exiled, you may look at them, you may cast permanent spells from among them, and you may spend mana as though it were mana of any color to cast those spells.

Haste

Whenever a Samurai or Warrior you control attacks alone, it gets +1/+0 until end of turn for each Samurai or Warrior you control.

Ashaya, Soul of the Wild's power and toughness are each equal to the number of lands you control.

Nontoken creatures you control are Forest lands in addition to their other types. (They're still affected by summoning sickness.)

When Ashen-Skin Zubera dies, target opponent discards a card for each Zubera that died this turn.

Flying

At the beginning of each end step, put a +1/+1 counter on Asmira, Holy Avenger for each creature put into your graveyard from the battlefield this turn.

Affinity for artifacts (This spell costs less to cast for each artifact you control.)

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Astral Cornucopia enters with X charge counters on it.

: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)

Enchant creature

When Astral Wingspan enters, draw a card.

Enchanted creature gets +2/+2 and has flying.

Flying, vigilance, deathtouch, lifelink

When Atraxa, Grand Unifier enters, reveal the top ten cards of your library. For each card type, you may put a card of that type from among the revealed cards into your hand. Put the rest on the bottom of your library in a random order. (Artifact, battle, creature, enchantment, instant, land, planeswalker, and sorcery are card types.)

Whenever you gain life for the first time each turn, create a 1/1 white Cat creature token.

: Another target Cleric gains lifelink until end of turn.

Enchant creature

Enchanted creature gets +2/+2 for each Aura attached to it and has vigilance.

Trample

Whenever Aurochs attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)

Trample

You may have Auton Soldier enter as a copy of any creature on the battlefield, except it isn't legendary, is an artifact in addition to its other types, and has myriad. (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.)

This spell costs less to cast for each opponent you have.

Trample

When Avatar of Growth enters, each player searches their library for up to two basic land cards, puts them onto the battlefield, then shuffles.

Reach, trample

Avatar of the Resolute enters with a +1/+1 counter on it for each other creature you control with a +1/+1 counter on it.

Amplify 1 <I>(As this creature enters, put a +1/+1 counter on it for each Bird and/or Soldier card you reveal in your hand.)</I>

Flying

As an additional cost to cast this spell, you may sacrifice any number of creatures. This spell costs less to cast for each creature sacrificed this way.

Each opponent sacrifices a creature. Create a 3/6 black and red Avatar creature token with haste and "Whenever this creature attacks, it deals 3 damage to each opponent."

Whenever one or more +1/+1 counters are put on Axgard Artisan for the first time each turn, create a Treasure token. (It's an artifact with ", Sacrifice this artifact: Add one mana of any color.")

Baki's Curse deals 2 damage to each creature for each Aura attached to that creature.

: Change the text of target white enchantment you control that doesn't have cumulative upkeep by replacing all instances of one color word with another. (For example, you may change "black creatures can't attack" to "blue creatures can't attack.") That enchantment gains "Cumulative upkeep ." (At the beginning of its controller's upkeep, that player puts an age counter on it, then sacrifices it unless they pay its upkeep cost for each age counter on it.)

Target opponent reveals their hand. You draw a card for each Mountain and red card in it.

Bane of Hanweir attacks each combat if able.

At the beginning of each upkeep, if a player cast two or more spells last turn, transform Bane of Hanweir.

Affinity for historic permanents (This spell costs less to cast for each artifact, legendary, and/or Saga permanent you control.)

When Banish to Another Universe enters, exile target nonland permanent an opponent controls until Banish to Another Universe leaves the battlefield.

Myriad (Whenever this creature 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.)

Whenever Banshee of the Dread Choir deals combat damage to a player, that player discards a card.

(Transforms from Thousand Moons Smithy.)

: Add .

Whenever you cast an artifact or creature spell using mana produced by Barracks of the Thousand, create a white Gnome Soldier artifact creature token with "This creature's power and toughness are each equal to the number of artifacts and/or creatures you control."

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for .)

Barricade Breaker attacks each combat if able.

Put a +1/+1 counter on each of up to two target creatures. You may search your library and/or graveyard for a card named Basri, Devoted Paladin, reveal it, and put it into your hand. If you search your library this way, shuffle.

When Bat Colony enters, create a 1/1 black Bat creature token with flying for each mana from a Cave spent to cast it.

Whenever a Cave you control enters, put a +1/+1 counter on target creature you control.

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for .)

Target creature gets -X/-X until end of turn. You gain X life.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)

I — Create a 1/1 white Human Warrior creature token.

II — Create a 1/1 green Elf Warrior creature token.

III — Choose any number of artifact tokens and/or creature tokens you control with different names. For each of them, create a token that's a copy of it.

, : Each opponent loses 2 life. This ability costs less to activate for each creature card in your graveyard.

Prevent all combat damage that would be dealt this turn if was spent to cast this spell. Each player loses 1 life for each attacking creature they control if was spent to cast this spell. (Do both if was spent.)

Equipped creature gets +1/+1 for each Dwarf, Equipment, and/or Vehicle you control.

Equip

One or two target creatures each gain haste until end of turn. For each of those creatures, create a Monster Role token attached to it. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1 and has trample.)

This spell costs less to cast for each instant and sorcery card in your graveyard.

Prowess

When Bedlam Reveler enters, discard your hand, then draw three cards.

At the beginning of each postcombat main phase, the active player adds for each of your opponents who lost life this turn. (Damage causes loss of life.)

Flying, hexproof

Megamorph (You may cast this card face down as a 2/2 creature for . Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

When Belltoll Dragon is turned face up, put a +1/+1 counter on each other Dragon creature you control.

Each player separates all nontoken lands they control into two piles. For each player, one of their piles is chosen by one of their opponents of their choice. Destroy all lands in the chosen piles. Tap all lands in the other piles.

Choose an opponent. You and that player each create three 1/1 white Spirit creature tokens with flying.

Choose an opponent. You gain 2 life for each creature you control and that player gains 2 life for each creature they control.

Devoid (This card has no color.)

When you cast this spell, for each opponent, choose a creature that player controls. Create a token that's a copy of one of those creatures, except its power is equal to the total power of those creatures, its toughness is equal to the total toughness of those creatures, and it's a colorless Eldrazi creature.

Whenever you cast an instant or sorcery spell that targets only Bill Potts or activate an ability that targets only Bill Potts, copy that spell or ability. You may choose new targets for the copy. This ability triggers only once each turn.

Doctor's companion (You can have two commanders if the other is the Doctor.)

Trample

Bioessence Hydra enters with a +1/+1 counter on it for each loyalty counter on planeswalkers you control.

Whenever one or more loyalty counters are put on planeswalkers you control, put that many +1/+1 counters on Bioessence Hydra.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)

I — Create a 2/2 white Astartes Warrior creature token with vigilance for each opponent you have.

II — Each opponent sacrifices a creature.

III — Draw two cards for each opponent who controls fewer creatures than you.

When Bishop of the Bloodstained enters, target opponent loses 1 life for each Vampire you control.

Search target player's library for a card and exile it. Then that player shuffles.

Gravestorm (When you cast this spell, copy it for each permanent put into a graveyard this turn. You may choose new targets for the copies.)

Whenever a creature dies, put a charge counter on Black Market.

At the beginning of your first main phase, add for each charge counter on Black Market.

Equipped creature gets +1/+1 for each land you control.

Equip legendary creature

Equip

When Bladecoil Serpent enters, for each spent to cast it, draw a card.

When Bladecoil Serpent enters, for each spent to cast it, each opponent discards a card.

When Bladecoil Serpent enters, for each spent to cast it, it gets +1/+0 and gains trample and haste until end of turn.

Flying, haste

Whenever Bladewing, Deathless Tyrant deals combat damage to a player or planeswalker, for each creature card in your graveyard, create a 2/2 black Zombie Knight creature token with menace.