Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Plains

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Thorough Investigation

Whenever you attack, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, venture into the dungeon. (Enter the first room or advance to the next room.)

Mondrak, Glory Dominus

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
{1}{W/P}{W/P}, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak, Glory Dominus. ({W/P} can be paid with either {W} or 2 life.)

Fateful Absence

Destroy target creature or planeswalker. Its controller investigates. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Mother of Runes

{T}: Target creature you control gains protection from the color of your choice until end of turn.

Thraben Inspector

When Thraben Inspector enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Filigree Vector

When Filigree Vector enters, put a +1/+1 counter on each of any number of target creatures and a charge counter on each of any number of target artifacts.
{1}, {T}, Sacrifice another artifact: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Phyrexia's Core

{T}: Add {C}.
{1}, {T}, Sacrifice an artifact: You gain 1 life.

Pearl Medallion

White spells you cast cost {1} less to cast.

Syr Ginger, the Meal Ender

Syr Ginger, the Meal Ender has trample, hexproof, and haste as long as an opponent controls a planeswalker.
Whenever another artifact you control is put into a graveyard from the battlefield, put a +1/+1 counter on Syr Ginger and scry 1.
{2}, {T}, Sacrifice Syr Ginger: You gain life equal to its power.

Of Herbs and Stewed Rabbit

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Put a +1/+1 counter on up to one target creature. Create a Food token.
II — Draw a card. Create a Food token.
III — Create a 1/1 white Halfling creature token for each Food you control.

Astrid Peth

Whenever Astrid Peth enters or attacks, create a Food token.
Brand-new Sky — Whenever you sacrifice a Clue or Food, Astrid Peth explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Arcbound Ravager

Sacrifice an artifact: Put a +1/+1 counter on Arcbound Ravager.
Modular 1 (This creature enters with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Hobbit's Sting

Hobbit's Sting deals X damage to target creature, where X is the number of creatures you control plus the number of Foods you control.

Rosie Cotton of South Lane

When Rosie Cotton of South Lane enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Whenever you create a token, put a +1/+1 counter on target creature you control other than Rosie.

Trading Post

{1}, {T}, Discard a card: You gain 4 life.
{1}, {T}, Pay 1 life: Create a 0/1 white Goat creature token.
{1}, {T}, Sacrifice a creature: Return target artifact card from your graveyard to your hand.
{1}, {T}, Sacrifice an artifact: Draw a card.

Sun Titan

Vigilance
Whenever Sun Titan enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Loran of the Third Path

Vigilance
When Loran of the Third Path enters, destroy up to one target artifact or enchantment.
{T}: You and target opponent each draw a card.

Darksteel Mutation

Enchant creature
Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Throne of Geth

{T}, Sacrifice an artifact: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Battle Angels of Tyr

Flying, myriad
Whenever Battle Angels of Tyr deals combat damage to a player, draw a card if that player has more cards in hand than each other player. Then you create a Treasure token if that player controls more lands than each other player. Then you gain 3 life if that player has more life than each other player.

Arcane Signet

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

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Eiganjo, Seat of the Empire

{T}: Add {W}.
Channel — {2}{W}, Discard Eiganjo, Seat of the Empire: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Sol Ring

Stroke of Midnight

Destroy target nonland permanent. Its controller creates a 1/1 white Human creature token.

Emeria, the Sky Ruin

Emeria, the Sky Ruin enters tapped.
At the beginning of your upkeep, if you control seven or more Plains, you may return target creature card from your graveyard to the battlefield.
{T}: Add {W}.

Field-Tested Frying Pan

When Field-Tested Frying Pan enters, create a Food token, then create a 1/1 white Halfling creature token and attach Field-Tested Frying Pan to it.
Equipped creature has "Whenever you gain life, this creature gets +X/+X until end of turn, where X is the amount of life you gained."
Equip {2}

Throne of Eldraine

As Throne of Eldraine enters, choose a color.
{T}: Add four mana of the chosen color. Spend this mana only to cast monocolored spells of that color.
{3}, {T}: Draw two cards. Spend only mana of the chosen color to activate this ability.