The Sadness Cube

Recently, I got hit by the idea of making a four-color half-cube. Nothing too out of the ordinary, right?

Here's what I'll be using for the basic land box:

Removing cost from consideration has... interesting... consequences.

Fish Have No Word For Water — Our Color Pie

General Notes

In this format, blue mana is so ubiquitous that it's effectively colorless. This manifests itself in one really interesting way: any and all blue mana costs are essentially generic mana costs.
Every single color is warped in some subtle way by incorporating some gold cards into their basic identity.

Blue Colorless

Bear in mind that these cards will be able to go into any deck.

This is maybe the biggest shift in the cube, so we might as well start with it. In this format, countering spells, drawing cards, and bouncing permanents are things that everyone can do, without needing to adjust your mana base in the slightest. The implications are pretty far-reaching, honestly.

Dimir Black

Why not be a jerk?

Honestly, this is going to be the least different of the colors — a splash of flash here, some cloning there, but mostly the same old black that we all know and love.

Izzet Prismari Red

How do you spell "flashy"?

Blue really brings out the "good at spells" part of red. This is appropriate, really — a cube with such easy access to counterspells is going to have some stack-fighting, and red is aggressive everywhere.

Simic Quandrix Green

Someone has to punch them in the face, right?

Green has actually been given a big ol' shove towards being the defacto "creature" color in the cube, since a lot of its land-manipulation tech just straight-up doesn't work on account of not having any basics. It'll just have to make do with solid creatures and top-deck manipulation.

Azorius White

The fun police have arrived!

White is even more of a killjoy than usual once Blue gets involved. Bear in mind that all of the flying lords are now mono-white. The future is now!
You're welcome to it! I'm far better at coming up with wacky ideas than I am at actually implementing them, so having someone else do all that hard work is just perfect. ;)

The Land Problem

One of the weirder consequences of using an untapped dual BLB is that it's actually incredibly difficult to pick alternative lands (since our "basics" are already on the upper end of our power level). This is even harder if we keep the restriction that every land has to be able to produce blue mana (since we want blue costs and generic costs to essentially be the same thing). This makes supporting decks with a lot of colors... tricky.

Aside: I'm Not Too Worried

This might actually be a cube where you don't want too much color fixing. I think 1-2 color decks (with added Blue, of course) are going to be the sweet spot here, since supporting three-color decks would be the equivalent of supporting four-color piles in a normal cube. However, if that's your goal... let's look at our options.

Utility Lands

Are these actually any good here?

OK, off the bat, these lands are really weakened by being in this kind of environment, now that they aren't color fixing. Fetid Pools is essentially just Polluted Mire here! The cube would probably have to be really slow to support getting any value out of these cards.

Snow Lands

Now there's actually a reason to run non-snow "basics" in your deck!

I'm just bringing these up to point out that we have the equivalent of tapped snow "basics", if we want them. Who knows, we might! Green Snow might be a possible theme to look into.

Our Tapped Trilands Duals

Hey, they're better than nothing.

These six lands are the equivalent of stuff like Cinder Barrens. They're thoroughly unexciting, and you can't fetch them or anything. I'm sad to say that there are actually worse trilands. Early Magic was a wild time. But can we do any better?

The Triomes Biomes

There, now that's fixed.

These cards are the equivalent to fetchable duals in this cube. It's annoying that they only cover three of the six color pairs, but that's what customs are (potentially) for! This does bring us to an important question, though:

Should We Run Fetchlands?

These are the only "safe" fetchlands.

Here's a fun fact: if we run any of the fetchlands that can fetch Islands, they can fetch any fetchable land. If we just run the above six and skip on running the Biomes, we have our "shockland" equivalent. If we do run the Biomes, however, that opens up decks that run three/four colors + Blue, which might make the Blue theme feel less obvious. I don't have a good answer on whether or not I want that or not.

Five Four Color Lands

I don't think we're going to run any of the "make any kind of mana you want, just with restrictions" lands. Had to mention them for completeness' sake, though.

Blue Colorless Utility Lands

We can't actually run any of the lands that just produce colorless mana, so these will have to do.

The above are pretty much all of the "colorless" lands we can run — I left out a few, like the mono-blue storage/depletion lands and Tolarian Academy, because I feel like they're on the extreme ends of playability. It could be somewhat interesting to use Thriving Isles as "wildcard" lands, though — they're whatever kind of basic you want when you play them.

Our Broad Archetypes

Since this is a small cube and I really "only" have four colors to play with, I've settled on supporting three major archetypes in Wedge colors. But before we get to that, I'd like to point out that there are two "simple" ways to divide the color triples in this set:

Ally vs. Enemy "Pairs": Yes, this old standbye still works here. In this case, the Ally "Pairs" would be Bant, Grixis, and Temur, while the Enemy Pairs would be Esper, Jeskai, and Sultai.
Wedges vs. Shards: This one should be pretty obvious, and it's the division we're going to go for — going for wedges gives me three obvious archetypes that I think would be fun to design around, so wedges it is.

Jeskai Lorehold Spells

I'm waiting for Lorehold and Prismari so hard, you guys.

Sultai Golgari Graveyard Shenanigans

I'll be honest — none of these archetypes particularly clever yet.

Temur Gruul Creatures

I actually kinda love Research as a straight-forward monogreen wish.