Booster Pack Game

The tide augurs have spoken. Let judgement commence!

Undercurrent Raider
I like the card but don't like the keyword. Compared to Phantom Warrior (what you yourself did) the card is rather weak and could have easily cost . But seeing that a 2/2, once buffed via an aura or counter, can be very hard to kill if it can only be blocked by 2-power guys, the is acceptable.
The keyword on the other hand is a little too number heavy for my tastes. can't be blocked by creatures with higher power or straight up can’t be blocked by creatures with power 2 or greater. without the number 2 in the rules would have been kind of fine. However, the mechanic is much like skulk from Shadows over Innistrad which was discarded for good reason.

Algatan Trencher
In a set with salvage as a main mechanic, graveyard matters is a theme to expect. This card plays well into this while still keeping the flavor of the plane. Good job!

Fish tribal isn't something I had in mind when I promted the set but it feels totally natural. I think you could have been a little bolder by also reducing the cost of krakens, octopi, sharks and whatnot.

All in all: Your cards are and show what the set is about. Diving, salvage, fish creatures... all your cards care about a different aspect of something that makes this plane unique. I wasn't wowed by any of your designs but they are solid and understandable. I also like the fact that you covered almost all the five colors and didn't just settle for blue as the easy way to go for this world.

Abyssal Returned
Sweet recursive creature that plays well into the themes of the set. On second thought, I think you could have added a may in the rules text but that's nothing I'd fight strongly about.

Oceanic Colossus
Simple and elegant flavor twist on Colossal Dreadmaw. I'm a bit sad that you didn't provide a render as artwork showing sea monsters is very easy to find and also has the tendency to look badass, so this feels like a missed opportunity.

Swift Moray
I guess Tuktuk Rubblefort severely lowered the bar on which rarity people expect a Creatures you control have haste to appear. I think this card is dangerously powerful but whether it is too powerful can only be decided after some testing so I'll give it the benefit of a doubt.

Depths of Disdain
Obvious cancel variant indeed. Or more like a twist of Dissolve. I like it and the flavor text made me laugh, so thumbs up!

Crackling Leviathan
A gigantic electric eel is a gorgeous idea and the p/t seems alright for its costs. I'm afraid though that the abilities of this guy will in the vast majority of cases only work as a deterrent. Preventing 5 damage by blocking this leviathan is almost never worth the inevitable bolt that follows suit, especially considering that it can hit you as well. I predict that this creature will either go unblocked or removed and will basically never bolt anything for real.

All in all: You were quite the driving force for this time of the challenge, designing more than a third of the booster. I liked Abyssal Returned, Oceanic Colossus and Depths of Disdain very much but wasn't too impressed with Swift Moray or Crackling Leviathan. However, none of your cards where bad or problematic whatsoever and I like that you covered almost all the five colors.

Deeper Still
This card feels like an obvious choice for a set with that mechanic and that's why I like it very much.

Seabed Predator
The flavor works here but I expect the gameplay against one or even multiple of these fish to be a pain. Creatures at common often only have first strike when attacking to prevent players from building walls of first strikes that can gang block everything to death. Your creature also encourages the player even more to just have it sit back and gum up the board. The hexproof makes it also invulnerable against 90% of removal in limited.

Electroburst Jelly
This card is really powerful for a common. It costs only more than Guttersnipe but has +0/+3 and can hit creatures and planeswalkers too! Oh and that's not even considering the fact that every form of power boost makes it so much stronger and can end the game with just a few opts (or Deeper Stills in this case). The defender is an irrelevant drawback most of the time.
I think the Jelly is too powerful, especially for a common, but I like the mechanical thinking behind it.

Jadescale Cloak
Elegant card with suitable flavor. Not much to say about it besides that I'm happy that you designed a noncreature card and didn't choose the easiest path of just doing some mana dork (number 2 out of 10 cards so far).

All in all: Your cards both work and make me believe that you made up your mind about what the set should look like in your opinion and what it needs to do that. Although Electroburst Jelly is, as I said, too powerful for a common imo it cleverly matches flavor and mechanics to a wholesome package.

viriss

Pearl Keeper
Glad that you designed a white card. The bottom card interaction is fine but doesn't really work with salvage because you either put the card into your graveyard or on the top of your library so revealing the bottom card and gaining life is a game of plain luck. The card's not bad, though, just a nonbo with certain elements of the set.

Auspicious Currents
Yeah, Favorable Winds for diving creatures. Not a bad idea considering how overproportional diving creatures benefit from p/t boosts because they get really hard to kill. The flavor works just fine. All in all, a straight forward and powerful card.

Come huddle around the fire, and try to forget about the howling snowstorms of Zhennore, the plane of ice and mist!

(By Anton Fadeev)

(By Ed Pulella)

Zhennore's sun is just a little farther away from the earth compared to most planes, so the whole plane is permanently frozen - around 45°F during the warmest months, and an average of -15°F during the depths of winter.

Despite this unforgiving climate, the humans that inhabit the plane have staked out a rather comfortable existence in their coal-powered cities, not straying too far into the ice-caked seas or massive boreal forests. Travelers know to head out heavily armed, as the polar bears, ice dragons, massive slugs, and yetis could easily destroy a party - not to mention the common and violent ice elementals that roam the wastes.

(By Huy Tran Viet)

Because the cold pierces through to the very soul of the plane, it's impossible to create fire with magic on Zhennore, which is why the people rely on good old-fashioned wood and coal. Spells that use water are also rare, as it tends to freeze before you can do anything useful with it.

Every seven days, like clockwork, a horrible blizzard sweeps across the entire plane. Animals hide, and people duck inside their homes or the temporary shelters constructed in the wilderness.

Some druids claim that meditating outdoors when the storm starts allows them to reach true enlightenment and power over the weather.

Recently, however, the days have been a few degrees warmer. There's less ice to break up in the harbor. An attacking elemental started to melt. It even rained yesterday - not even sleet!
Some praise this as a miracle, but others are wary - as they should be. What's going to happen to the weekly blizzard? Zhennore's very soul is made of ice, and if that melts... what would be left?

Reprint:

Enchantment — Aura
Enchant creature
Enchanted creature has base power and toughness 0/4, has defender, loses all other abilities, and is a blue Wall in addition to its other colors and types.

Mechanical themes:

-Snow permanents and Snowflux in every color (As an additional cost to cast this spell, you may sacrifice a snow permanent. If you do, ...)

-The return of Outlast and +1/+1 counter synergy

-Elemental tribal in blue, white, and black
-A lack of fire magic - Even red mages use ice on Zhennore, although lightning and geomancy are also on the table.

-I'm not great at designing new keyword abilities, but I'd love to see what you come up with!

Common #1:

Snow Creature - Elemental

Snowflux - As an additional cost to cast ~, you may sacrifice a snow permanent. If you do, when ~ enters the battlefield, target creature gets -2/-2 until end of turn.

3/2

Good luck!

EDIT: Added a Tap it. rider to make it less oppressive.