Venomsac Lagac

Deathtouch
Whenever this creature attacks while saddled, it gets +0/+3 until end of turn.
Saddle 2 (Tap any number of other creatures you control with total power 2 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Martyr's Soul

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 this creature enters, if you control no tapped lands, put two +1/+1 counters on it.

Oreskos Sun Guide

Inspired — Whenever this creature becomes untapped, you gain 2 life.

Trained Arynx

Whenever this creature attacks while saddled, it gains first strike until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Saddle 2 (Tap any number of other creatures you control with total power 2 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Drover Grizzly

Whenever this creature attacks while saddled, creatures you control gain trample until end of turn.
Saddle 1 (Tap any number of other creatures you control with total power 1 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Stonybrook Schoolmaster

Whenever this creature becomes tapped, you may create a 1/1 blue Merfolk Wizard creature token.

Starfighter Pilot

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

Samite Healer

{T}: Prevent the next 1 damage that would be dealt to any target this turn.

Attentive Sunscribe

Whenever this creature becomes tapped, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Compassionate Healer

Whenever this creature becomes tapped, you gain 1 life and scry 1. (Look at the top card of your library. You may put it on the bottom.)

Unexpected Assistance

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.)
Draw three cards, then discard a card.

Command Bridge

This land enters tapped.
When this land enters, sacrifice it unless you tap an untapped permanent you control.
{T}: Add one mana of any color.

Night Market Lookout

Whenever this creature becomes tapped, each opponent loses 1 life and you gain 1 life.

Servant of Tymaret

Inspired — Whenever this creature becomes untapped, each opponent loses 1 life. You gain life equal to the life lost this way.
{2}{B}: Regenerate this creature.

Brightfield Mustang

Whenever this creature attacks while saddled, untap it and put a +1/+1 counter on it.
Saddle 1 (Tap any number of other creatures you control with total power 1 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Judge of Currents

Whenever a Merfolk you control becomes tapped, you may gain 1 life.

Spider-Gwen, Free Spirit

Reach
Whenever Spider-Gwen becomes tapped, you may discard a card. If you do, draw a card.

Deepwater Hypnotist

Inspired — Whenever this creature becomes untapped, target creature an opponent controls gets -3/-0 until end of turn.

Temporal Cleansing

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.)
The owner of target nonland permanent puts it into their library second from the top or on the bottom.

Goblin Medics

Whenever this creature becomes tapped, it deals 1 damage to any target.

Focus Fire

Focus Fire deals X damage to target attacking or blocking creature, where X is 2 plus the number of creatures and/or Spacecraft you control.

Merrow Skyswimmer

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.)
Flying, vigilance
When this creature enters, create a 1/1 white and blue Merfolk creature token.

Silvergill Peddler

Whenever this creature becomes tapped, draw a card, then discard a card.

Thunderhead Squadron

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.)
Flying

Giant Beaver

Vigilance
Whenever this creature attacks while saddled, put a +1/+1 counter on target creature that saddled it this turn.
Saddle 3 (Tap any number of other creatures you control with total power 3 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

Moonfolk Puzzlemaker

Flying
Whenever this creature becomes tapped, scry 1.

Rescue Leopard

Whenever this creature becomes tapped, you may discard a card. If you do, draw a card.

Sun-Dappled Celebrant

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.)
Vigilance

Spireside Infiltrator

Whenever this creature becomes tapped, it deals 1 damage to each opponent.

Nanoform Sentinel

Whenever this creature becomes tapped, untap another target permanent. This ability triggers only once each turn.