This is my take on Mono-Black 8-Rack. I'm trying some things out and will be doing the same with Davriel once WAR is released. Guide is not accurate right now. Making changes to deck.

Discard

4x Inquisition of Kozilek , 4x Raven's Crime , 3x Thoughtseize , 2x Wrench Mind

Inquisition of Kozilek & Thoughtseize are great at taking away early plays and cantrips away from the opponent. This slows them down and allows you to survive longer and therefore give you a higher chance to win. Raven's Crime is cheap repeatable discard that can sometimes just machine gun down an opponents hand. Putting lands into the graveyard with this card also helps to consistently enable Hostile Desert , one of the new cards I'm trying out. Wrench Mind is a almost always a 2-for-1 play that actively works you towards your goal.

Removal

1x Dismember , 3x Fatal Push

Dismember is in to deal with any large threats that evade Fatal Push or a down tick from Liliana of the Veil . Fatal Push is a great one-mana removal spell and is really effective at slowing down aggressive creature decks allowing you to prolong the game. With the current build, you have 2 Field of Ruin , 2 black fetches, and 4 Smallpox to primarily turn on revolt along with other assorted ways to lose permanents.

Rack Effects

4x The Rack , 4x Shrieking Affliction

The Rack & Shrieking Affliction are your finishers and where the name of the deck comes from. It is usually in your best interest to hold onto these until they can begin lowering our opponent's life total to dodge removal that you may get rid of with your discard. You should also play Shrieking Affliction first if your opponent can be kept consistently at one card because the extra point of life can make a difference. The Rack should be played first if the opponent is consistently at two cards so it can chip in one damage each turn. Of course, if your opponent is consistently at zero cards then order does not matter. It is a reasonable consideration to play out these effects first if an opponent can threaten your hand with discard.

Versatile Cards

4x Liliana of the Veil , 4x Smallpox , 2x Collective Brutality , 2x Surgical Extraction

Liliana of the Veil does both things you want out of a card in this deck, repeatable discard and repeatable removal. Dropping a Liliana of the Veil on turn three and ticking down to clean any threats off the board that were missed by your other removal and then ticking up every turn can win a game. It is quite rare that you will reach her ult but it is devastating if reached. Smallpox does a lot to slow the opponent down. Removal, discard, and land destruction all in one package is a bomb when played correctly. I tend to wait for a creature to hit the board before playing this card but depending on the situation it can sometimes be better to fire it off as soon as possible. The more aggressive play is good against control decks since it puts them a turn further from casting Cryptic Command and attacks the valuable resources in their hand. Surgical Extraction is a tentative addition in the current graveyard heavy meta with Dredge and Arclight Phoenix decks taking center stage along with the threat light Grixis Death Shadow that can be rendered impotent by stripping out what threats they do have. I have 2 of this card currently in the mainboard but may reduce it to 1 if I find it isn't useful enough to warrant 2. This card also have the corner case of ripping out one of the three Tron lands and changing the Tron matchup from nearly unwinnable to even.

Lands

2x Polluted Delta , 4x Mutavault , 10x Swamp , 4x Urborg, Tomb of Yawgmoth , 2x Field of Ruin , 1x Hostile Desert

Polluted Delta can be replaced by any black fetch. It is in the deck to turn on revolt for Fatal Push and also to enable Hostile Desert . Mutavault is another way to pressure the opponent's life total and can block a lethal swing in a pinch. Swamp is a pretty obvious choice for a mono-black deck. Urborg, Tomb of Yawgmoth turn Polluted Delta , Mutavault , Hostile Desert , and Field of Ruin into lands that tap for . Additional copies can be pitched to Raven's Crime & up ticks from Liliana of the Veil to in turn enable Hostile Desert . The land total is so high for a deck with such a low curve to turn on Raven's Crime and also for padding against the symmetry of Liliana of the Veil 's up tick. Field of Ruin is an excellent utility land that helps to slow down Tron, prevent death by manland, stop Amulet Titan from doing Amulet Titan things, and force a shuffle after a 2 top scry from a Serum Visions or a 0, or Jacestorm, from Jace, the Mind Sculptor . Hostile Desert is some new tech I am trying out to help close games faster and keep up with the speed of Modern. I've mentioned throughout ways to enable this threat but I will give a comprehensive list here: Retrace from Raven's Crime , escalating Collective Brutality , sacrificing a land to Smallpox , pitching a land to a Liliana of the Veil uptick, activating Field of Ruin , fetching with a black fetch, and blocking something with a Mutavault . The infastructure of the deck can support this card but I am still uncertain if the card will make a large enough impact to prevent being replaced by a Swamp .

Sideboard

2x Bontu's Last Reckoning , 4x Delirium Skeins , 4x Leyline of the Void , 2x Collective Brutality , 2 Ensnaring Bridge , 1 Liliana, the Last Hope

Bontu's Last Reckoning comes in against creature heavy decks to extend the game. Delirium Skeins comes in against decks with Leyline of Sanctity since it dodges hexproof along with Liliana of the Veil . A more common use for this card is boarding it in for control in place of removal. Control is great a consistently drumming up card advantage and making them discard 3 cards is devastating for them. The same goes for combo decks. Leyline of the Void comes in against graveyard reliant decks like Dredge and Living End. I don't believe this should be brought in against Arclight Phoenix as Phoenix can be taken away with Surgical Extraction and the other threats can be dealed with by the means of standard removal. Collective Brutality comes in against Arclight Phoenix and Burn over Thoughtseize because it has the option to gain life instead of the certainty of losing it. It also has the ability to remove a creature from the board and strip a spell from the opponents all at the same time! (Also this spell still resolves if it is cast targeting legal targets and those legal targets go away before the resolution of the spell.) Ensnaring Bridge is a common 8-Rack card used to totally take away the ability to attack since 8-Rack can dump it's hand rather quickly. I am including it in the sideboard instead of the mainboard partially because it limits Hostile Desert and partially because it doesn't feel very impactful currently. We can still win games without it but it also is a good tool to have in the sideboard against decks that like to win with creatures and have a tough time removing artifacts. Liliana, the Last Hope is a great overall card and a nice piece to bring out of the sideboard. It effectively eliminates 2 power creatures and has the upside of killing 1 toughness creatures. I may stick a couple Dark Confidant in the sideboard to better utilize the downtick of this card. Fulminator Mage is also an option in this case. Liliana, the Last Hope is also a quasi-win condition if you can reach her ultimate. If you are concerned about Rack effects being removed this card can provide insurance in another form of victory.