Rivals of Ixalan

Deeproot Elite | Creature | Merfolk Warrior | Whenever another Merfolk enters the battlefield under your control, put a +1/+1 counter on target Merfolk you control. | Winona Nelson

Ghalta, Primal Hunger | Legendary Creature | Elder Dinosaur | This spell costs {X} less to cast, where X is the total power of creatures you control. Trample | Chase Stone

Jadelight Ranger | Creature | Merfolk Scout Ranger | When Jadelight Ranger enters the battlefield, it explores, then it explores again. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard. Then repeat this process.) | Jason Rainville

Path of Discovery | Enchantment | | Whenever a creature enters the battlefield under your control, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.) | Howard Lyon

Tendershoot Dryad | Creature | Dryad | Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.) At the beginning of each upkeep, create a 1/1 green Saproling creature token. Saprolings you control get +2/+2 as long as you have the city's blessing. | Yongjae Choi

Wayward Swordtooth | Creature | Dinosaur | Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.) You may play an additional land on each of your turns. Wayward Swordtooth can't attack or block unless you have the city's blessing. | Chris Rahn

World Shaper | Creature | Merfolk Shaman | Whenever World Shaper attacks, you may mill three cards. When World Shaper dies, return all land cards from your graveyard to the battlefield tapped. | Raymond Swanland

Siegehorn Ceratops | Creature | Dinosaur | Enrage — Whenever Siegehorn Ceratops is dealt damage, put two +1/+1 counters on it. (It must survive the damage to get the counters.) | Filip Burburan

Hadana's Climb | Legendary Enchantment | | At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. Then if that creature has three or more +1/+1 counters on it, transform Hadana's Climb. | Titus Lunter

Journey to Eternity | Legendary Enchantment | Aura | Enchant creature you control When enchanted creature dies, return it to the battlefield under your control, then return Journey to Eternity to the battlefield transformed under your control. | Deruchenko Alexander