Braids, Cabal Minion is very powerful.
Smokestack needs more support to really be broken, but I think the tools exist for it to be very strong.
Death Cloud is one of my favorite cards and the main reason to go heavy black IMO. It does everything. It armageddons, it wraths, it makes hands disappear, it even fireballs. Card is ridiculous.
So a few lines you can follow to incorporate. Most obvious is the Pox archetype rooted mainly in black. Use recursive creatures like crawler/bloodghast/2 shields to break symmetry, add
Smallpox for redundancy. This works really well with hand destruction and things like thoughtsieze. Resource denial early in particular until you get one of these engines online is really important. You can go deep and run things like
Lake of the Dead and
Necropotence. That's surprisingly strong because you can quickly get to 5 mana, use necro to ensure you never miss lands and that gets your engine online faster. Super risky line of play but that's what makes it fun.
This archetype has lots of places to overlap. Most obvious is tokens. Things like lingering souls and then white anthems make this a natural pairing. You are sacing tokens while they are sacing important things. This also pairs nicely with white hate bears. Again, you want to prevent them from building up their board early in particular, so
mana tithe and annoying crap like Thalia help to delay them until Braids and company are doing damage.
Vindicate a land is also not unreasonable.
In red, this can work with the aristocrats theme. Getting you double duty out of the sacrificed creatures you have to lose to Braids/Smokestack. Blood artists, goblin bombardment, goblin token producing cards, etc. Going red gets you burn which allows you to pick off creatures making the Braids/Smokestack hit more important things like lands.
In green, there's
life from the loam to get back all the lands you sac to your own braids/smokestack. The new Magus of the Crucible I imagine fits right in here (along with actual
Crucible of Worlds).
Exploration effects are super good here since you can outpace the trigger. Outside token producers, this might be the easiest way to ramp Smokestack up to 2+ soot counters and not have it destroy your own board.
All in all, I think it's definitely worth supporting at higher power levels. Very flavorful and bleeds well into a lot of colors if you use your imagination.