Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters the battlefield, untap all creatures.

Lavinia, Azorius Renegade

Each opponent can't cast noncreature spells with mana value greater than the number of lands that player controls.
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.

End-Raze Forerunners

Vigilance, trample, haste
When End-Raze Forerunners enters the battlefield, other creatures you control get +2/+2 and gain vigilance and trample until end of turn.

Gyre Engineer

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Dream Stalker

When Dream Stalker enters the battlefield, return a permanent you control to its owner's hand.

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Stonecloaker

Flash
Flying
When Stonecloaker enters the battlefield, return a creature you control to its owner's hand.
When Stonecloaker enters the battlefield, exile target card from a graveyard.

Elvish Visionary

When Elvish Visionary enters the battlefield, draw a card.

Mulldrifter

Flying
When Mulldrifter enters the battlefield, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Absorb

Clever Impersonator

You may have Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.

Mana Breach

Whenever a player casts a spell, that player returns a land they control to its owner's hand.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Village Bell-Ringer

Flash (You may cast this spell any time you could cast an instant.)
When Village Bell-Ringer enters the battlefield, untap all creatures you control.

Overwhelmed Apprentice

When Overwhelmed Apprentice enters the battlefield, each opponent mills two cards. Then you scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

District Guide

When District Guide enters the battlefield, you may search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Shrieking Drake

Flying
When Shrieking Drake enters the battlefield, return a creature you control to its owner's hand.

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Overburden

Whenever a player puts a nontoken creature onto the battlefield, that player returns a land they control to its owner's hand.

Chulane, Teller of Tales

Vigilance
Whenever you cast a creature spell, draw a card, then you may put a land card from your hand onto the battlefield.
{3}, {T}: Return target creature you control to its owner's hand.

Moss Diamond

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

Sea Gate Oracle

When Sea Gate Oracle enters the battlefield, look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Sphinx's Tutelage

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.

Bronzehide Lion

{G}{W}: Bronzehide Lion gains indestructible until end of turn.
When Bronzehide Lion dies, return it to the battlefield. It's an Aura enchantment with enchant creature you control and "{G}{W}: Enchanted creature gains indestructible until end of turn," and it loses all other abilities.

Frilled Mystic

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

Risen Reef

Whenever Risen Reef or another Elemental enters the battlefield under your control, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

Whitemane Lion

Flash
When Whitemane Lion enters the battlefield, return a creature you control to its owner's hand.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

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

Faerie Formation

Flying
{3}{U}: Create a 1/1 blue Faerie creature token with flying. Draw a card.

Lotus Cobra

Landfall — Whenever a land enters the battlefield under your control, add one mana of any color.