When Merfolk Tunnel-Guide enters the battlefield, you get a three-time boon with "Whenever one or more Merfolk enter the battlefield under your control, target Merfolk creature you control explores."
2/2
Mycoid Resurrection - 4BG
Sorcery (Rare)
Fathomless descent - Each creature card in your graveyard perpetually gets +X/+X, where X is the number of permanent cards in your graveyard. Then return a creature card from your graveyard to the battlefield.
Reflection Net - 1WU
Artifact (Uncommon)
Flash
When Reflection Net enters the battlefield, exile target creature until Reflection Net leaves the battlefield.
2: Target creature you control becomes a copy of a creature card exiled with Reflection Net. Activate only as a sorcery and only once.
Scalesoul Gnome - 3RW
Artifact Creature - Gnome (Rare)
Trample, Haste Whenever Scalesoul Gnome deals combat damage to a player, discover X, where X is that damage.
Whenever you play a card from exile, conjure a duplicate of it into your hand.
3/5
Tan Jolom, the Worldwalker - 1GWU
Legendary Creature - Spirit (Rare)
At the beginning of combat on your turn, choose up to one target artifact or land you control that isn't a creature or token. Until end of turn, it becomes a 3/3 Spirit creature with vigilance and double team in addition to its other types.
3/3
Mycelic Ballad - 3B
Sorcery - Chorus (Rare)
Starting intensity 2 Each player sacrifices X creatures and you gain X life, where X is this spell's intensity.
All Chorus cards you own intensify by 1.
Phantasmal Extraction - 1U
Sorcery (Uncommon)
If you weren't the starting player, this spell costs less to cast.
Target opponent reveals each nonland card in their hand with mana value 4 or less. Choose a card revealed this way or a card in their graveyard. Exile that card.
Stalwart Speartail - 1RG
Creature - Dinosaur
Enrage - Whenever Stalwart Speartail is dealt damage, other Dinosaurs you control and Dinosaur cards in your hand and library perpetually get +1/+1.
Whenever Stalwart Speartail attacks, you may pay 3. When you do, Stalwart Speartail deals 1 damage to each creature and each planeswalker.