All 1 and 2 drop simic merfolk, fairly cheap and low to the ground. Changes could include Hadana's Climb, Deeproot Waters, or Kumena if you want to increase the mana curve slightly. Removal would be limited to things like Expel from Orazca and Nature's Way if you're keeping in theme. I considered Curious Obsession and Cartouche of Knowledge, but your mileage may vary on those.
This is not meant to be hyper competitive. It's a strange, silly theme deck for Rivals standard that may surprise and get some people. I'm sure it would be better with other cards, but it acts as a good aggro shell to start with until you see your meta, and the sideboard is highly customizable for what you're facing. I would caution to leave in the four Negates to deal with later unconditional wipes like Fumigate and big wins like Approach, and Spell Pierces to take care of the smaller pains like Golden Demise, Sweltering Suns and Fiery Canonade. Heroic Intervention will save your whole board from some nonsense, but can be considered a more narrow counter for wipes and should only be used if you need to trick your opponent into some bad attacks as well as stop sweepers.
V0.2: Took out two Kumena's Speakers in favor of 2 Hadana's Climbs. The speakers are decent one drops, but are possibly the least valued card in the deck. Having the extra push of a flipped climb is a good alternative.
V0.3: Put back in the Speakers. Climb is too slow. Dropped a Jade Bearer and a Chart a Course for two Kumena to round it out instead.
Vo.4 Swapped out some forests for Hashep's Oasis. Can't believe I forgot about this, perfect for pushing through some last damage on an unblockable fish. Swapped Hadana's Climb in the sideboard for UG Nissa. Cards I'm considering on the fringes are swapping some of the Heralds for things like Branchwalkers, dropping a mimic for another Tyrant, and maybe adding another forest in there somewhere. This deck doesn't rely on counter synergy with Herald of Secret Streams to get through damage, so it needs a critical mass of unblockable threats to do that instead.
