Most of these derive from outside suggestions by scrad_the_wanderer that in some cases have been slightly refined. Those are denoted with a star.
WU: tempo *
This deck uses detain, other pacifism effects, blue tricks and so on to get a tempo advantage over the opponent.
UB: brainwash *
This deck is all about messing with brainwash and with -1/-1 counters.
BR: aggro / burn
An aggro deck with low curve, that wants to use cheap creatures and punishment effects like Lavaborn Muse, Blightning, Liliana's Caress, Anathemancer, Breath of Malfegor, Havoc Festival, Mudbutton Torchrunner, Rabid Bloodsucker to get the opponent low on life before closing the game with burn spells.
The creatures of this deck will be mostly Rebels, to take advantage of embolden. Some of them will have embolden thenselves. This deck will also use embolden instants and sorceries.
GW: Rebel tribal
A tribal deck taking advantage of classic tribal synergies ("Rebel creatures you control get +1/+1", "Whenever a Rebel creature enters the battlefield under your control", and such) as opposed to RG that is also a Rebel deck but focused on embolden.
WB: grindy control *
This archetype is going to have a lot of removal and restraining cards.
UR: artifacts / Implants *
This is the archetype that deals with the chips, implants and drones. Red has the Ministry of Industry that makes a lot of sense here.
Ramp can make sense in black. It still has the ability to care about Swamps and such, check out the infamous Liliana of the Dark Realms. This is well explained in this post by NegativeFiveBelow:
Quote from NegativeFiveBelow »I like those archetypes, but how exactly are we going to do black ramp? Black rituals aren't a thing anymore, and any color can search for it's corresponding basic land, so that is not something that is unique to black. an example of black ramp woul be Liliana's Shade, but then again, we have Knight of the White Orchid and landcycling.
While colors are allowed to search for their own basic lands, black and green care the most about their respective basic lands. In addition to cards like Crypt Ghast mentioned above, earching gatherer for "each (land type) you control" yields far more results for BG than any other color pair. In particular, black and green are the colors that have creatures with abilities that set their stats to the number of their particular lands you control (Dungrove Elder, Kalonian Twingrove, Nightmare, Squelching Leeches).
Also, the original reason I suggested BG ramp is because of black's top end; black, to me, has cool options for excess mana at uncommon in the form of its X spells. Things like Consume Spirit, Exsanguinate, and Postmortem Lunge (and at rare, Mind Shatter and X-costed wraths like Black Sun's Zenith), combined with green's large creatures at the top of the curve, give a ramp player options for how to end a game after he's gotten to absurd amounts of mana.
RW: recruit aggro *
An aggro deck focusing on recruit. Plain, simple, and fast.
GU: playing with counters: brainwash + counter-moving effects *
This is the "fun with counters" deck, with blue brainwashing and moving counters around and green passing them to the opponent or removing them altogether.