Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Feldon's Cane

{T}, Exile Feldon's Cane: Shuffle your graveyard into your library.

Forest

Jade Guardian

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
When Jade Guardian enters, put a +1/+1 counter on target Merfolk you control.

Weather the Storm

You gain 3 life.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Umara Entangler

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Dive Down

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Woodland Stream

Woodland Stream enters tapped.
{T}: Add {G} or {U}.

Mist-Cloaked Herald

Jungleborn Pioneer

When Jungleborn Pioneer enters, create a 1/1 blue Merfolk creature token with hexproof. (It can't be the target of spells or abilities your opponents control.)

Vector Glider

The Modern Age

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Draw a card, then discard a card.
III — Exile this Saga, then return it to the battlefield transformed under your control.

The Modern Age // Vector Glider

Master's Rebuke

Target creature you control deals damage equal to its power to target creature or planeswalker you don't control.

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

River Heralds' Boon

Put a +1/+1 counter on target creature and a +1/+1 counter on up to one target Merfolk.

Generous Ent

Reach
When Generous Ent enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Forestcycling {1} ({1}, Discard this card: Search your library for a Forest card, reveal it, put it into your hand, then shuffle.)

Lull

Prevent all combat damage that would be dealt this turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Shaper Apprentice

Shaper Apprentice has flying as long as you control another Merfolk.

Unsummon

Return target creature to its owner's hand.

Island

Negate

Jade Bearer

When Jade Bearer enters, put a +1/+1 counter on another target Merfolk you control.

Broken Bond

Destroy target artifact or enchantment. You may put a land card from your hand onto the battlefield.