Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Sol Ring

Peregrine Drake

Flying
When Peregrine Drake enters, untap up to five lands.

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Acidic Slime enters, destroy target artifact, enchantment, or land.

Inga and Esika

Creatures you control have vigilance and "{T}: Add one mana of any color. Spend this mana only to cast a creature spell."
Whenever you cast a creature spell, if three or more mana from creatures was spent to cast it, draw a card.

Tatyova, Benthic Druid

Landfall — Whenever a land you control enters, you gain 1 life and draw a card.

Simic Guildgate

This land enters tapped.
{T}: Add {G} or {U}.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Kinnan, Bonder Prodigy

Whenever you tap a nonland permanent for mana, add one mana of any type that permanent produced.
{5}{G}{U}: Look at the top five cards of your library. You may put a non-Human creature card from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Wildheart Invoker

{8}: Target creature gets +5/+5 and gains trample until end of turn. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Moritte of the Frost

Changeling (This card is every creature type.)
You may have Moritte of the Frost enter as a copy of a permanent you control, except it's legendary and snow in addition to its other types and, if it's a creature, it enters with two additional +1/+1 counters on it and has changeling.

Simic Signet

Moss Diamond

Moss Diamond enters tapped.
{T}: Add {G}.

Seasonal Ritual

Add one mana of any color. (Then exile this card. You may cast the creature later from exile.)

Rosethorn Acolyte

Rosethorn Acolyte // Seasonal Ritual

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Gyre Engineer

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Maraleaf Pixie

Biomancer's Familiar

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.
{T}: The next time target creature adapts this turn, it adapts as though it had no +1/+1 counters on it.

Thornwood Falls

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {U}.

Leafkin Druid

{T}: Add {G}. If you control four or more creatures, add {G}{G} instead.

Kodama's Reach

Counterspell

Frilled Mystic

Flash
When Frilled Mystic enters, you may counter target spell.

Negate

Paladin of Predation

Toxic 6 (Players dealt combat damage by this creature also get six poison counters.)
Paladin of Predation can't be blocked by creatures with power 2 or less.

Keeper of Fables

Whenever one or more non-Human creatures you control deal combat damage to a player, draw a card.

Minor Misstep

Counter target spell with mana value 1 or less.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Mana Leak

Counter target spell unless its controller pays {3}.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Emergent Woodwurm

Backup 3 (When this creature enters, put three +1/+1 counters on target creature. If that's another creature, it gains the following ability until end of turn.)
Whenever this creature attacks, look at the top X cards of your library, where X is its power. You may put a permanent card with mana value X or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Tishana's Tidebinder

Flash
When Tishana's Tidebinder enters, counter up to one target activated or triggered ability. If an ability of an artifact, creature, or planeswalker is countered this way, that permanent loses all abilities for as long as Tishana's Tidebinder remains on the battlefield. (Mana abilities can't be targeted.)

In Search of Greatness

At the beginning of your upkeep, you may cast a permanent spell from your hand with mana value equal to 1 plus the highest mana value among other permanents you control without paying its mana cost. If you don't, scry 1.

Gretchen Titchwillow

{2}{G}{U}: Draw a card. You may put a land card from your hand onto the battlefield.

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If Incubation Druid has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Paradise Druid

This creature has hexproof as long as it's untapped. (It can't be the target of spells or abilities your opponents control.)
{T}: Add one mana of any color.

Copy Enchantment

You may have Copy Enchantment enter as a copy of any enchantment on the battlefield.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Ground Seal

When Ground Seal enters, draw a card.
Cards in graveyards can't be the targets of spells or abilities.

Lullmage's Familiar

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

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Leyline of Abundance

If Leyline of Abundance is in your opening hand, you may begin the game with it on the battlefield.
Whenever you tap a creature for mana, add an additional {G}.
{6}{G}{G}: Put a +1/+1 counter on each creature you control.

Prime Speaker Zegana

Prime Speaker Zegana enters with X +1/+1 counters on it, where X is the greatest power among other creatures you control.
When Prime Speaker Zegana enters, draw cards equal to its power.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Tribute Mage

When Tribute Mage enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.