Ixalan did what it could to push the tribal synergies with Dinosaurs, but it never really happened. Vampires made a small splash at Pro Tour Ixalan, but it fade quickly. Players were hopeful that the addition of Rivals of Ixalan and a banning to Energy and Mono-Red would shake things up a bit… and maybe it has.
The Merfolk don’t have the most powerful cards. If you look at a Merfolk deck in Modern, the best cards are the Lords. Merfolk Mistbinder is a much stronger card in a powered-down format like Standard than it is in Legacy or Vintage, and it helps to tie all of your synergies together. Merfolk have a great ability to get aggressive, which means that you’re going to want a good curve and some ways to pump your cheaper creatures. A 2/2 for 2 is a fair rate and pumping your entire team makes this the most valuable card in the deck.
The Merfolk can get on the board early as they have access to a number of quality 1-drop creatures. Kumena’s Speaker is the best of these, as it should virtually always be a 2/2 for just 1 mana in this deck. That rate shouldn’t blow anyone away, but it is quite strong in a deck with cheap ways to pump its creatures. Mist-Cloaked Herald has demonstrated its talents in Rivals Limited as a tough creature to deal with before it gets in too much damage. Combining a 1-mana unblockable creature with cheap and efficient pump effects is excellent.
Silvergill Adept continues to reward you for playing heavy Merfolk. A 2/1 creature for 2 is not a good rate, but it’s serviceable and will get into the red zone. The extra card makes sure that you continue to have fuel to power out your fish.
Along this same vein is Merfolk Branchwalker. You have a lot less control over what the Branchwalker gives you, but the floor is awfully similar to an Adept in a 2/1 creature that draws you a land. A 3/2 creature with the option to scry into your graveyard is also quite nice, and a 2-drop that can size up this well before pump effects can apply a lot of pressure.
Kumena, Tyrant of Orazca has a number of relevant abilities that can break open a stalled-out game. The problem with playing a bunch of small synergistic creatures is that you can definitely get brickwalled. There is also the potential problem of not wanting to send your entire team into a Settle the Wreckage. Kumena solves these nicely. Not only can you utilize your other Merfolk to make Kumena unblockable, but you can tap your board of Merfolk to draw additional cards or pump up your team with +1/+1 counters. Both of these abilities can be game-breaking even if they are a little slow.
Watertrap Weaver is another way to break through an opponent’s defenses. Creatures like Silvergill Adept and Kumena’s Speaker are solid, but a 4/4 on the other side of the table does a great job of stopping your entire attack. Watertrap Weaver makes sure that you can get a couple of nice attacks in before a creature can untap.
Your pump effects are fantastic. River Heralds’ Boon is not just a Limited MVP, as a 2-mana spell that adds 2 power and 2 toughness at instant speed among multiple creatures can be absolutely incredible. Blossoming Defense gives you more ways to win in combat or counter a removal spell on your important Merfolk. Curious Obsession can be a blowout when cast into open mana, namely red for a Shock effect or black for a Fatal Push. Against a tapped out opponent, however, Obsession will immediately deal an extra point and replace the card you cast with a fresh one for only a single mana. If they untap and have the removal spell, so be it, but if they don’t then it’s lights out. If you have a Blossoming Defense to protect your creature, Obsession can run away with the game.
Bounce effects are almost always card disadvantage, so you don’t see them too often in Constructed without a good reason. A single mana to bounce a creature can provide tremendous tempo for an aggro deck or save your own important creature from a removal spell. Unsummon does these jobs nicely and can even bounce your Adepts or Branchwalkers in a pinch to see more cards.
Merfolk haven’t had the chance to shine in Standard for a long time, but the addition of Rivals of Ixalan may have changed all of that. With cheap aggressive creatures and a new lord, Merfolk are back!