Universal Surveillance

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Draw X cards.

Goldvein Hydra

Vigilance, trample, haste
This creature enters with X +1/+1 counters on it.
When this creature dies, create a number of tapped Treasure tokens equal to its power.

Ultros, Obnoxious Octopus

Whenever you cast a noncreature spell, if at least four mana was spent to cast it, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a noncreature spell, if at least eight mana was spent to cast it, put eight +1/+1 counters on Ultros.

Weaver of Currents

Up the Beanstalk

When this enchantment enters and whenever you cast a spell with mana value 5 or greater, draw a card.

Spectral Denial

This spell costs {1} less to cast for each creature you control with power 4 or greater.
Counter target spell unless its controller pays {X}.

Stream of Life

Infirmary Healer

This creature enters prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Infirmary Healer // Stream of Life

Garruk's Uprising

When this enchantment enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever a creature you control with power 4 or greater enters, draw a card.

Fractalize

Until end of turn, target creature becomes a green and blue Fractal with base power and toughness each equal to X plus 1. (It loses all other colors and creature types.)

Divergent Equation

Return up to X target instant and/or sorcery cards from your graveyard to your hand.
Exile Divergent Equation.

Tanufel Rimespeaker

Whenever you cast a spell with mana value 4 or greater, draw a card.

Harmonize

Gene Pollinator

{T}, Tap an untapped permanent you control: Add one mana of any color.

Hermitic Herbalist

{T}: Add one mana of any color.
{T}: Add two mana in any combination of colors. Spend this mana only to cast Lesson spells.

Wild Hypothesis

Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it.
Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Biomass Mutation

Creatures you control have base power and toughness X/X until end of turn.

Nev, the Practical Dean

Creatures you control with counters on them have trample.
Whenever you cast your first spell with {X} in its mana cost each turn, put X +1/+1 counters on Nev.

Hardbristle Bandit

{T}: Add one mana of any color.
Whenever you commit a crime, untap this creature. This ability triggers only once each turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Procrastinate

Tap target creature. Put twice X stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Scan the Clouds

Draw two cards, then discard two cards. (Then exile this card. You may cast the creature later from exile.)

Tempest Hart

Trample
Whenever you cast a spell with mana value 5 or greater, put a +1/+1 counter on this creature.

Tempest Hart // Scan the Clouds

Syncopate

Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Troyan, Gutsy Explorer

{T}: Add {G}{U}. Spend this mana only to cast spells with mana value 5 or greater or spells with {X} in their mana costs.
{U}, {T}: Draw a card, then discard a card.

Summon: Fenrir

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Crescent Fang — Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
II — Heavenward Howl — When you next cast a creature spell this turn, that creature enters with an additional +1/+1 counter on it.
III — Ecliptic Growl — Draw a card if you control the creature with the greatest power or tied for the greatest power.

Broodguard Elite

This creature enters with X +1/+1 counters on it.
When this creature leaves the battlefield, put its counters on target creature you control.
Warp {X}{G} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Ingenious Prodigy

Skulk (This creature can't be blocked by creatures with greater power.)
This creature enters with X +1/+1 counters on it.
At the beginning of your upkeep, if this creature has one or more +1/+1 counters on it, you may remove a +1/+1 counter from it. If you do, draw a card.

Utopia Sprawl

Enchant Forest
As this Aura enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Trash the Town

Spree (Choose one or more additional costs.)
+ {2} — Put two +1/+1 counters on target creature.
+ {1} — Target creature gains trample until end of turn.
+ {1} — Until end of turn, target creature gains "Whenever this creature deals combat damage to a player, draw two cards."

Druid of the Cowl

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.

Open into Wonder

X target creatures can't be blocked this turn. Until end of turn, those creatures gain "Whenever this creature deals combat damage to a player, draw a card."

Raucous Audience

{T}: Add {G}. If you control a creature with power 4 or greater, add {G}{G} instead.

Mind into Matter

Draw X cards. Then you may put a permanent card with mana value X or less from your hand onto the battlefield tapped.

Geometer's Arthropod

Whenever you cast a spell with {X} in its mana cost, look at the top X cards of your library. Put one of them into your hand and the rest on the bottom of your library in a random order.

Wildwood Rebirth

Return target creature card from your graveyard to your hand.

Rampaging Yao Guai

Vigilance, trample
This creature enters with X +1/+1 counters on it.
When this creature enters, destroy any number of target artifacts and/or enchantments with total mana value X or less.

Muse Seeker

Opus — Whenever you cast an instant or sorcery spell, draw a card. Then discard a card unless five or more mana was spent to cast that spell.

Pterafractyl

Flying
This creature enters with X +1/+1 counters on it.
When this creature enters, you gain 2 life.