Venerated Loxodon

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
When Venerated Loxodon enters, put a +1/+1 counter on each creature that convoked it.

Gleeful Demolition

Destroy target artifact. If you controlled that artifact, create three 1/1 red Phyrexian Goblin creature tokens.

Kuldotha Rebirth

As an additional cost to cast this spell, sacrifice an artifact.
Create three 1/1 red Goblin creature tokens.

Witchstalker Frenzy

This spell costs {1} less to cast for each creature that attacked this turn.
Witchstalker Frenzy deals 5 damage to target creature.

Roiling Vortex

At the beginning of each player's upkeep, Roiling Vortex deals 1 damage to them.
Whenever a player casts a spell, if no mana was spent to cast that spell, Roiling Vortex deals 5 damage to that player.
{R}: Your opponents can't gain life this turn.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, Warleader's Call deals 1 damage to each opponent.

Case of the Gateway Express

When this Case enters, choose target creature you don't control. Each creature you control deals 1 damage to that creature.
To solve — Three or more creatures attacked this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Creatures you control get +1/+0.

Lightshield Array

At the beginning of your end step, put a +1/+1 counter on each creature that attacked this turn.
Sacrifice Lightshield Array: Creatures you control gain hexproof and indestructible until end of turn.

Invasion of Gobakhan

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Gobakhan enters, look at target opponent's hand. You may exile a nonland card from it. For as long as that card remains exiled, its owner may play it. A spell cast this way costs {2} more to cast.

Invasion of Gobakhan // Lightshield Array

Arid Mesa

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Regal Bunnicorn

Regal Bunnicorn's power and toughness are each equal to the number of nonland permanents you control.

Pithing Needle

As Pithing Needle enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Mountain

Novice Inspector

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

Train Troops

Create two 2/2 white Knight creature tokens with vigilance. (Then exile this card. You may cast the creature later from exile.)

Imodane's Recruiter

When Imodane's Recruiter enters, creatures you control get +1/+0 and gain haste until end of turn.

Imodane's Recruiter // Train Troops

Plains

Obsidian Charmaw

This spell costs {1} less to cast for each land your opponents control that could produce {C}.
Flying
When Obsidian Charmaw enters, destroy target nonbasic land an opponent controls.

Resolute Reinforcements

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, create a 1/1 white Soldier creature token.

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.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Knight-Errant of Eos

Convoke
When Knight-Errant of Eos enters, look at the top six cards of your library. You may reveal up to two creature cards with mana value X or less from among them, where X is the number of creatures that convoked Knight-Errant of Eos. Put the revealed cards into your hand, then shuffle.

Thraben Inspector

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