merfolk deck mtg commander precon Magic: The Gathering The Lost Caverns of Ixalan Commander - Merfolk precon upgrade

Glorybringer and The Scarab God might define what five mana buys in the format, but its not hard to play Regisaur Alpha or Charging Monstrosaur for four

City of Brass makes you take one damage when it is tapped and can give you one mana of any color in return and, likewise, Mana Confluence adds one mana of any color but has the requirement of paying one life

Heart of Kiran takes a hit since Thorn Lieutenant cant outright crew it, but this impressive card replaces itself if destroyed, cant be targeted or pushed around by aggressive creatures, and it protects from flooding late in the game by providing a 6/7 attacker fore five mana

The cards are designed with their mechanics first in a spreadsheet, with rarity assigned according to certain stats and text

this type of repeated creature generation works nicely in a sacrifice deck, where you can let those Snails serve a higher cause by making mana or being used for spells