Bojuka Bubbler
Creature — Elemental Ooze
At the beginning of your end step, sacrifice a non-Swamp land. When you do, put a +1/+1 counter on Bojuka Bubbler, search your library for a basic Swamp card, put it onto the battlefield, then shuffle.
"Even this muck is truer and better than the chalky scars of nothing." — Nissa
2/2

Dust Devourer

Creature - Eldrazi Drone (R)
3/2

Devoid (This creature has no color.)
Sacrifice a land: Create a 1/1 colorless Eldrazi Scion creature token with "Sacrifice this creature: Add ."

There was a terrible cacophony, and then silence.

Bear-Strength Blesser
Creature — Elf Warrior Cleric
Kicker
When enters the battlefield, if it was kicked, put a +1/+1 counter on each of up to one target Warrior, up to one target Cleric, up to one target Wizard, and/or up to one target Rogue.
2/2

Armored Geopede

Creature - Insect (U)
2/2

Landfall - Whenever a land enters the battlefield under your control, Armored Geopede gets +0/+2 until end of turn.
: Armored Geopede's power becomes its toughness until end of turn.

Unlocking of the Eye
Enchantment — Saga
I - Search your library for a planeswalker card, reveal it, put it into your hand, then shuffle.
II - Unlocking of the Eye deals 3 damage to any target.
III - Put an Eldrazi card in your graveyard or a face-up Eldrazi card you own in exile into your hand. Create two 0/1 colorless Eldrazi Eldrazi Spawn creature tokens. They have ", Sacrifice this Eldrazi Spawn: Add ."

Terramorphic Rift
Land (R)

: Add .
, , Sacrifice two lands: Search your library for up to two basic land cards and put them onto the battlefield tapped, then shuffle.

Innistrad

One of Us!
Sorcery
Exile target nonland permanent an opponent controls. Its controller creates a token that's a copy of target creature you control.
"We don't like strangers here. But you don't have to be a stranger."

Hopping Skaab

Creature - Zombie (U)
4/3

When Hopping Skaab enters the battlefield, you may draw two cards, then discard two cards.
Exile a creature card from your graveyard: Hopping Skaab gains flying until end of turn.

Cemetery Rite

Enchantment (R)
At the beginning of combat on your turn, exile a creature card from a graveyard. If you do, create a tapped 2/2 black Zombie creature token. It doesn't untap during your untap step for as long as you control Cemetery Rite.
Whenever there are no creature cards in graveyards, sacrifice Cemetery Rite.

Serial Artist
Creature — Vampire Noble
: Serial Artist deals 1 damage to target creature or planeswalker.
Whenever a creature or planeswalker dealt damage by this turn dies, create a Clue Treasure artifact token named Masterpiece. It has ", Sacrifice Masterpiece: Add one mana of any color," and ", , Sacrifice Masterpiece: Draw a card."
"This is the first of my latest series."
1/2

Undying Hunger
Sorcery
Target creature you control gains undying until end of turn. It fights target creature you don't control.
Flashback
The terror is not that there are monsters outside. The terror is that you always had a monster inside.

The Fall of Dusk Flight
Enchantment — Saga
I - Search your library for a card, shuffle, and put that card on top. You lose 2 life.
II - Exile target nonland permanent an opponent controls.
III - Search target opponent's library, hand, and/or graveyard for any number of cards that share a name with the exiled card and exile those cards. If that player's library is searched this way, they shuffle.

Cracked Tombstone
Artifact — Clue
, , Sacrifice Cracked Tombstone: Draw a card.
, , Sacrifice a Clue: Return target creature card from your graveyard to your hand.

Abandoned Shrine
Land
: Add .
Flashback
When Avacyn turned against the people, they turned to new faiths, not knowing their prayers were going to the same enormity that corrupted the archangel.

Onto Theros!

Pantheon's Reckoning

Sorcery (R)
For each white permanent, destroy that permanent unless its controller's devotion that color is five or greater. Repeat this process for blue, black, red, and green.
As the war between the gods raged, even mortals were forced to choose sides.

Syzygy
Sorcery
Exile all enchantments you control, then return them to the battlefield.
"You know me as the god of horizons, but I was born when the first mortal looked at the sky and wondered. I am older than the gods, the titans, even destiny." — Keranos

We can probably add Arcavios (home of Strixhaven) to the first post now.

Filthdragger Enforcer
Enchantment Creature — Harpy
Flying
Bestow
Enchanted creature gets -2/-1.
The first death can come quietly or viciously. But for the Returned, Erebos's grasp only comes cruelly.
2/1

Muse-Given Inspiration

Sorcery (R)
Exile the top three cards of your library. Until the end of turn, you may play those cards.
Add an amount of equal to your devotion to red.

Threads of Klothys
Instant
Exile target nonland permanent that escaped.
"You may think the threads of fate constraining, but do you hate the woven cloak that keeps you warm or the woven roof that keeps you dry?" — Calix

Ironic End

Instant (U)
Target creature assigns combat damage to itself this turn.
"There is no more just punishment that that which you sought to inflict on another." —Verenes, priest of Iroas