Thurid, Mare of Destiny

Copy

Flying, lifelink
Whenever you cast a Pegasus, Unicorn, or Horse creature spell, copy it. (The copy becomes a token.)
Other Pegasi, Unicorns, and Horses you control get +1/+1.

Muse Drake

Flying
When this creature enters, draw a card.

Mystic Skyfish

Whenever you draw your second card each turn, this creature gains flying until end of turn.

Nadir Kraken

Tentacle

Whenever you draw a card, you may pay {1}. If you do, put a +1/+1 counter on this creature and create a 1/1 blue Tentacle creature token.

Naiad of Hidden Coves

During turns other than yours, spells you cast cost {1} less to cast.

Network Disruptor

Flying
When this creature enters, tap target permanent.

Nightveil Sprite

Flying
Whenever this creature attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When this enchantment enters, scry 2, then draw a card.
{2}{U}, Sacrifice this enchantment: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Oneirophage

Flying
Whenever you draw a card, put a +1/+1 counter on this creature.

Opportunity

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Urdnan, Dromoka Warrior

When Urdnan enters, put a +1/+1 counter on target creature.
Whenever you attack, target attacking creature with a +1/+1 counter on it gains first strike until end of turn. If that creature has two or more +1/+1 counters on it, it gains double strike until end of turn instead.

Organ Hoarder

When this creature enters, look at the top three cards of your library, then put one of them into your hand and the rest into your graveyard.

Foundations Jumpstart