Sydri, Galvanic Genius

{U}: Target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value until end of turn.
{W}{B}: Target artifact creature gains deathtouch and lifelink until end of turn.

Greasefang, Okiba Boss

At the beginning of combat on your turn, return target Vehicle card from your graveyard to the battlefield. It gains haste. Return it to its owner's hand at the beginning of your next end step.

Grist, the Hunger Tide

As long as Grist, the Hunger Tide isn't on the battlefield, it's a 1/1 Insect creature in addition to its other types.
+1: Create a 1/1 black and green Insect creature token, then mill a card. If an Insect card was milled this way, put a loyalty counter on Grist and repeat this process.
−2: You may sacrifice a creature. When you do, destroy target creature or planeswalker.
−5: Each opponent loses life equal to the number of creature cards in your graveyard.

Henzie "Toolbox" Torre

Each creature spell you cast with mana value 4 or greater has blitz. The blitz cost is equal to its mana cost. (You may choose to cast that spell for its blitz cost. If you do it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)
Blitz costs you pay cost {1} less for each time you've cast your commander from the command zone this game.

Thelon of Havenwood

Each Fungus creature gets +1/+1 for each spore counter on it.
{B}{G}, Exile a Fungus card from a graveyard: Put a spore counter on each Fungus on the battlefield.

Alela, Artful Provocateur

Flying, deathtouch, lifelink
Other creatures you control with flying get +1/+0.
Whenever you cast an artifact or enchantment spell, create a 1/1 blue Faerie creature token with flying.

Shallow Grave

Return the top creature card of your graveyard to the battlefield. That creature gains haste until end of turn. Exile it at the beginning of the next end step.

Entomb

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

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Dark Ritual

Rionya, Fire Dancer

At the beginning of combat on your turn, create X tokens that are copies of another target creature you control, where X is one plus the number of instant and sorcery spells you've cast this turn. They gain haste. Exile them at the beginning of the next end step.

Zabaz, the Glimmerwasp

Modular 1
If a modular triggered ability would put one or more +1/+1 counters on a creature you control, that many plus one +1/+1 counters are put on it instead.
{R}: Destroy target artifact you control.
{W}: Zabaz, the Glimmerwasp gains flying until end of turn.

Demonic Consultation

Choose a card name. Exile the top six cards of your library, then reveal cards from the top of your library until you reveal a card with the chosen name. Put that card into your hand and exile all other cards revealed this way.

Old Rutstein

When Old Rutstein enters and at the beginning of your upkeep, mill a card. If a land card is milled this way, create a Treasure token. If a creature card is milled this way, create a 1/1 green Insect creature token. If a noncreature, nonland card is milled this way, create a Blood token.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Virtus the Veiled

Partner with Gorm the Great (When this creature enters, target player may put Gorm into their hand from their library, then shuffle.)
Deathtouch
Whenever Virtus the Veiled deals combat damage to a player, that player loses half their life, rounded up.

Astor, Bearer of Blades

When Astor, Bearer of Blades enters, look at the top seven cards of your library. You may reveal an Equipment or Vehicle card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Equipment you control have equip {1}.
Vehicles you control have crew 1.

Umbris, Fear Manifest

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.
Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land card.

Depala, Pilot Exemplar

Other Dwarves you control get +1/+1.
Each Vehicle you control gets +1/+1 as long as it's a creature.
Whenever Depala, Pilot Exemplar becomes tapped, you may pay {X}. If you do, reveal the top X cards of your library, put all Dwarf and Vehicle cards from among them into your hand, then put the rest on the bottom of your library in a random order.

Gorm the Great

Partner with Virtus the Veiled (When this creature enters, target player may put Virtus into their hand from their library, then shuffle.)
Vigilance
Gorm the Great must be blocked if able, and Gorm must be blocked by two or more creatures if able.

Willowdusk, Essence Seer

{1}, {T}: Choose another target creature. Put a number of +1/+1 counters on it equal to the amount of life you gained this turn or the amount of life you lost this turn, whichever is greater. Activate only as a sorcery.

Gemstone Caverns

If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand.
{T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

Mazzy, Truesword Paladin

Whenever an enchanted creature attacks one of your opponents, it gets +2/+0 and gains trample until end of turn.
Whenever an Aura you control is put into your graveyard from the battlefield, exile it. Until the end of your next turn, you may cast that card.