Harbinger of the Seas

Primal Druid

When Primal Druid dies, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Plains

Sekki, Seasons' Guide

Sekki, Seasons' Guide enters with eight +1/+1 counters on it.
If damage would be dealt to Sekki, prevent that damage, remove that many +1/+1 counters from Sekki, and create that many 1/1 colorless Spirit creature tokens.
Sacrifice eight Spirits: Return Sekki from your graveyard to the battlefield.

Iname as One

When Iname as One enters, if you cast it from your hand, you may search your library for a Spirit permanent card, put it onto the battlefield, then shuffle.
When Iname as One dies, you may exile it. If you do, return target Spirit permanent card from your graveyard to the battlefield.

Swamp

Forbidding Spirit

When Forbidding Spirit enters, until your next turn, creatures can't attack you or planeswalkers you control unless their controller pays {2} for each of those creatures.

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Necrodominance

Skip your draw step.
At the beginning of your end step, you may pay any amount of life. If you do, draw that many cards.
Your maximum hand size is five.
If a card or token would be put into your graveyard from anywhere, exile it instead.

Emperor of Bones

At the beginning of combat on your turn, exile up to one target card from a graveyard.
{1}{B}: Adapt 2.
Whenever one or more +1/+1 counters are put on Emperor of Bones, put a creature card exiled with Emperor of Bones onto the battlefield under your control with a finality counter on it. It gains haste. Sacrifice it at the beginning of the next end step.

Yavimaya Elder

When Yavimaya Elder dies, you may search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.
{2}, Sacrifice Yavimaya Elder: Draw a card.

Permeating Mass

Whenever Permeating Mass deals combat damage to a creature, that creature becomes a copy of Permeating Mass.

Willow Geist

Trample
Whenever one or more cards leave your graveyard, put a +1/+1 counter on Willow Geist.
When Willow Geist dies, you gain life equal to its power.

Sakura-Tribe Elder

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

Forest

Indebted Spirit

Bestow {2}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached.)
Afterlife 1 (When this permanent is put into a graveyard from the battlefield, create a 1/1 white and black Spirit creature token with flying.)
Enchanted creature gets +1/+1 and has afterlife 1.

Winter Moon

Players can't untap more than one nonbasic land during their untap steps.

Strangleroot Geist

Haste
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Myojin of Life's Web

Myojin of Life's Web enters with a divinity counter on it if you cast it from your hand.
Myojin of Life's Web has indestructible as long as it has a divinity counter on it.
Remove a divinity counter from Myojin of Life's Web: Put any number of creature cards from your hand onto the battlefield.

Iname, Death Aspect

When Iname, Death Aspect enters, you may search your library for any number of Spirit cards, put them into your graveyard, then shuffle.

Lifespinner

{T}, Sacrifice three Spirits: Search your library for a legendary Spirit permanent card, put it onto the battlefield, then shuffle.

Vile Entomber

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, search your library for a card, put that card into your graveyard, then shuffle.

Primal Prayers

When Primal Prayers enters, you get {E}{E} (two energy counters).
You may cast creature spells with mana value 3 or less by paying {E} rather than paying their mana costs. If you cast a spell this way, you may cast it as though it had flash.

Eladamri, Korvecdal

You may look at the top card of your library any time.
You may cast creature spells from the top of your library.
{G}, {T}, Tap two untapped creatures you control: Reveal a card from your hand or the top card of your library. If you reveal a creature card this way, put it onto the battlefield. Activate only during your turn.

Birthing Ritual

At the beginning of your end step, if you control a creature, look at the top seven cards of your library. Then you may sacrifice a creature. If you do, you may put a creature card with mana value X or less from among those cards onto the battlefield, where X is 1 plus the sacrificed creature's mana value. Put the rest on the bottom of your library in a random order.

Eladamri's Call

Search your library for a creature card, reveal that card, put it into your hand, then shuffle.