Helga, Skittish Seer

Whenever you cast a creature spell with mana value 4 or greater, you draw a card, gain 1 life, and put a +1/+1 counter on Helga, Skittish Seer.
{T}: Add X mana of any one color, where X is Helga, Skittish Seer's power. Spend this mana only to cast creature spells with mana value 4 or greater or creature spells with {X} in their mana costs.

Narod, the Beige Flower

Each creature assigns combat damage equal to its mana value rather than its power.

Byode, Inverse Sun

+2: Mill three cards, then return any number of cards from different Universes milled this way from your graveyard to your hand.
-X: Choose a Universe you haven't chosen this way this game. You may cast a spell from that Universe with mana value X or less from your hand without paying its mana cost.
Byode, Inverse Sun can be your commander.
Your deck can include Universes Beyond cards of any color identity.

Slivdrazi Monstrosity

Eldrazi you control are Slivers in addition to their other types.
Slivers you control have devoid and annihilator 1.
{3}: Create a 1/1 colorless Eldrazi Sliver creature token. It has "Sacrifice this creature: Add {C}."

The Mindskinner

The Mindskinner can't be blocked.
If a source you control would deal damage to an opponent, prevent that damage and each opponent mills that many cards.

Kemba, Kha Regent

At the beginning of your upkeep, create a 2/2 white Cat creature token for each Equipment attached to Kemba, Kha Regent.

Glissa, Herald of Predation

At the beginning of combat on your turn, choose one —
• Incubate 2 twice. (To incubate 2, create an Incubator token with two +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)
• Transform all Incubator tokens you control.
• Phyrexians you control gain first strike and deathtouch until end of turn.

Yenna, Redtooth Regent

{2}, {T}: Choose target enchantment you control that doesn't have the same name as another permanent you control. Create a token that's a copy of it, except it isn't legendary. If the token is an Aura, untap Yenna, Redtooth Regent, then scry 2. Activate only as a sorcery.

Shelob, Child of Ungoliant

Deathtouch, ward {2}
Other Spiders you control have deathtouch and ward {2}.
Whenever another creature dealt damage this turn by a Spider you controlled dies, create a token that's a copy of that creature, except it's a Food artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life," and it loses all other card types.

Rendmaw, Creaking Nest

Menace, reach
When Rendmaw, Creaking Nest enters and whenever you play a card with two or more card types, each player creates a tapped 2/2 black Bird creature token with flying. The tokens are goaded for the rest of the game. (They attack each combat if able and attack a player other than you if able.)

Vren, the Relentless

Ward {2}
If a creature an opponent controls would die, exile it instead.
At the beginning of each end step, create X 1/1 black Rat creature tokens with "This creature gets +1/+1 for each other Rat you control," where X is the number of creatures your opponents controlled that were exiled this turn.

Zimone, Mystery Unraveler

Landfall — Whenever a land you control enters, manifest dread if this is the first time this ability has resolved this turn. Otherwise, you may turn a permanent you control face up. (To manifest dread, look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Kona, Rescue Beastie

Survival — At the beginning of your second main phase, if Kona, Rescue Beastie is tapped, you may put a permanent card from your hand onto the battlefield.

Fynn, the Fangbearer

Deathtouch
Whenever a creature you control with deathtouch deals combat damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Andrios, Roaming Explorer

Reach
As long as Andrios is attacking, tapped creatures you control with base power and toughness 4/3 have base power and toughness 16/9.
{T}: Add {W}{U}{B}{R}{G}. Creature spells you spend this mana to cast have their base power and toughness become 4/3.

Fludge, Gunk Guardian

Whenever Fludge, Gunk Guardian or another Slug, Ooze, Fungus, or Mutant enters the battlefield under your control, each opponent shuffles three Gunk cards into their library. (Gunk is a colorless sorcery card with no mana cost that has cycling {4}.)

Sauron, the Dark Lord

Ward—Sacrifice a legendary artifact or legendary creature.
Whenever an opponent casts a spell, amass Orcs 1.
Whenever an Army you control deals combat damage to a player, the Ring tempts you.
Whenever the Ring tempts you, you may discard your hand. If you do, draw four cards.

Erestor of the Council

Whenever players finish voting, each opponent who voted for a choice you voted for creates a Treasure token. You scry X, where X is the number of opponents who voted for a choice you didn't vote for. Draw a card.

Elusen, the Giving

Flying, vigilance, lifelink, haste
At the beginning of your second main phase, the player to your left gains control of Elusen, the Giving.
Whenever a player donates a permanent to another player, the donating player draws a card, gains 1 life, and creates three Treasure tokens.

Gothmog, Morgul Lieutenant

When Gothmog, Morgul Lieutenant enters, amass Orcs 1. (Put a +1/+1 counter on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)
Creature tokens you control have deathtouch.

Valgavoth, Harrower of Souls

Flying
Ward—Pay 2 life.
Whenever an opponent loses life for the first time during each of their turns, put a +1/+1 counter on Valgavoth, Harrower of Souls and draw a card.

M'Odo, the Gnarled Oracle

Eminence — {X}, Discard a card: Target player reveals cards from the top of their library until they reveal a creature card with converted mana cost X or less. Put that card onto the battlefield under your control, then that player shuffles the rest into their library. Activate this ability only if M'Odo, the Gnarled Oracle is on the battlefield or in the command zone.

Kharis & The Beholder

Flying
When Kharis & The Beholder enters and at the beginning of your upkeep, create a 1/1 white Human creature token and make a charisma check. (Roll a d20.)
• If the result plus the number of creatures you control is greater than 11, put a +1/+1 counter on each creature you control.
• If the result is a natural 20, for each nonlegendary creature you control, create a token that's a copy of that creature.

Arabella, Abandoned Doll

Whenever Arabella, Abandoned Doll attacks, it deals X damage to each opponent and you gain X life, where X is the number of creatures you control with power 2 or less.

Marina Vendrell

When Marina Vendrell enters, reveal the top seven cards of your library. Put all enchantment cards from among them into your hand and the rest on the bottom of your library in a random order.
{T}: Lock or unlock a door of target Room you control. Activate only as a sorcery.

Urtet, Remnant of Memnarch

Whenever you cast a Myr spell, create a 1/1 colorless Myr artifact creature token.
At the beginning of combat on your turn, untap each Myr you control.
{W}{U}{B}{R}{G}, {T}: Put three +1/+1 counters on each Myr you control. Activate only during your turn.