Caterwauling Boggart

Goblins you control and Elementals you control have menace. (They can't be blocked except by two or more creatures.)

Goblin Scouts

Create three 1/1 red Goblin Scout creature tokens with mountainwalk. (They can't be blocked as long as defending player controls a Mountain.)

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Amphibian Accident

Until end of turn, target creature loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Accident-Prone Apprentice

Whenever you cast a noncreature spell, Accident-Prone Apprentice perpetually gets +1/+1. This ability also triggers if Accident-Prone Apprentice is in exile.

Accident-Prone Apprentice // Amphibian Accident

Call

Create four 1/1 white Bird creature tokens with flying.
Fuse (You may cast one or both halves of this card from your hand.)

Beck

Whenever a creature enters this turn, you may draw a card.
Fuse (You may cast one or both halves of this card from your hand.)

Beck // Call

Auntie's Snitch

Auntie's Snitch can't block.
Prowl {1}{B} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Goblin or Rogue.)
Whenever a Goblin or Rogue you control deals combat damage to a player, if Auntie's Snitch is in your graveyard, you may return Auntie's Snitch to your hand.

Circle of Protection: Green

{1}: The next time a green source of your choice would deal damage to you this turn, prevent that damage.

Byrke, Long Ear of the Law

Vigilance
When Byrke, Long Ear of the Law enters, put a +1/+1 counter on each of up to two target creatures.
Whenever a creature you control with a +1/+1 counter on it attacks, double the number of +1/+1 counters on it.

Hydradoodle

As Hydradoodle enters, roll X six-sided dice. Hydradoodle enters with a number of +1/+1 counters on it equal to the total of those results.
Reach, trample

Ecological Appreciation

Search your library and graveyard for up to four creature cards with different names that each have mana value X or less and reveal them. An opponent chooses two of those cards. Shuffle the chosen cards into your library and put the rest onto the battlefield. Exile Ecological Appreciation.

Croakid Amphibonaut

Croakid Amphibonaut has flying as long as you control a stickered permanent.

Duergar Cave-Guard

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{R/W}: Duergar Cave-Guard gets +1/+0 until end of turn.

Ellywick Tumblestrum

+1: Venture into the dungeon. (Enter the first room or advance to the next room.)
−2: Look at the top six cards of your library. You may reveal a creature card from among them and put it into your hand. If it's legendary, you gain 3 life. Put the rest on the bottom of your library in a random order.
−7: You get an emblem with "Creatures you control have trample and haste and get +2/+2 for each differently named dungeon you've completed."

Boggart Birth Rite

Return target Goblin card from your graveyard to your hand.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Entangling Trap

Whenever you clash, tap target creature an opponent controls. If you won, that creature doesn't untap during its controller's next untap step. (This ability triggers after the clash ends.)

Ambitious Assault

Creatures you control get +2/+0 until end of turn. If you control a modified creature, draw a card. (Equipment, Auras you control, and counters are modifications.)

Explore

You may play an additional land this turn.
Draw a card.

Frogtosser Banneret

Haste
Goblin spells and Rogue spells you cast cost {1} less to cast.

Fatal Push

Destroy target creature if it has mana value 2 or less.
Revolt — Destroy that creature if it has mana value 4 or less instead if a permanent you controlled left the battlefield this turn.

Thalia and The Gitrog Monster

First strike, deathtouch
You may play an additional land on each of your turns.
Creatures and nonbasic lands your opponents control enter tapped.
Whenever Thalia and The Gitrog Monster attacks, sacrifice a creature or land, then draw a card.

Alchemist's Refuge

{T}: Add {C}.
{G}{U}, {T}: You may cast spells this turn as though they had flash.

Earwig Squad

Prowl {2}{B} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Goblin or Rogue.)
When Earwig Squad enters, if its prowl cost was paid, search target opponent's library for three cards and exile them. Then that player shuffles.

Ellywick Tumblestrum Emblem

Creatures you control have trample and haste and get +2/+2 for each differently named dungeon you've completed.

Thalia and The Gitrog Monster // Thalia and The Gitrog Monster

Food

{2}, {T}, Sacrifice this token: You gain 3 life.

Baki's Curse

Baki's Curse deals 2 damage to each creature for each Aura attached to that creature.

Fire-Lit Thicket

{T}: Add {C}.
{R/G}, {T}: Add {R}{R}, {R}{G}, or {G}{G}.

Baloth Pup

Baloth Pup has trample as long as it has a +1/+1 counter on it.

Arcbound Fiend

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
At the beginning of your upkeep, you may move a +1/+1 counter from target creature onto Arcbound Fiend.
Modular 3 (This creature enters with three +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Frogkin Kidnapper

When Frogkin Kidnapper enters, target opponent reveals their hand. Choose a nonland card from it. Ransom that card. (Exile it. Its owner may pay {3} at any time to return it to their hand.)