So this is my current Blue-Black control deck. Not running Thoughtsieze for now but that might change.
One card that has been performing much better than expected in my deck is Monastery Siege, since the extra card draw lets you draw into the cards you need while also filling the graveyard so you can cast Dig Through Time as cheaply as possible.
There are 4 main deck copies of Drown in Sorrow in my list because I found myself coming up against a lot of Mardu and Jeskai decks containing cards such as Goblin Rabblemaster and Ponyback Brigade and I want to keep my copies of Bile Blight for slightly more resilient creatures like Mantis Rider and Mardu Hordechief. After game one in these match-ups, I tend to bring in 3x Jorubai Murk Lurker in exchange for 2x Disdainful Stroke and a copy of Crux of Fate. Silumgar, the Drifting Death is a great replacement to Pearl Lake Ancient against token strategies as he can clear the board at the cost of taking a longer time to kill your opponent.
In Abzan matchups, where the creatures are tougher but a little more expensive, I would look to use Crux of Fate to clear the board once a creature or two comes out. Two real problem cards this deck comes across when playing against Abzan are Anafenza, the Foremost and Citadel Siege. Anafenza is in a great place against this deck as her low mana cost keeps her out of range of Disdainful Stroke while her four toughness makes here resistant to both Drown in Sorrow and Bile Blight, meaning that the only way to deal with her is Hero's Downfall if you let her resolve. If my opponent resolves Citadel Siege and chooses Dragons in game one then I find that I won't be able to win unless I get both of my creatures out. Because of this, it is VERY important to counter this spell when the Abzan player tries to play it. After game one, I usually bring in 2x Negate, 2x Disdainful Stroke and 2x Perilous Vault in exchange for 3x Bile Blight and 3x Drown in Sorrow. While a bit clunky to use as a sweeper, Perilous Vault is the deck's main way of removing Citadel Siege once it resolves.
Against Sultai Delve and Sultai Whip, this deck does well as long as a counter-spell is kept in hand to cancel Whip of Erebos as almost everything else the decks tend to do can be handled by my other cards as long as this is kept off of the field. While all of the the removal the deck has in game one fuels delve by putting cards in the opposing graveyard, this can be remedied a little in games two and three by bringing in Perilous Vault to exile things instead. This also deals with the higher toughness cards that these decks sometimes run. One card that this deck interacts strangely with is Rakshasa Deathdealer. While the deck doesn't offer many ways to counter or remove this card once it resolves due to its regeneration and pump abilities, I've found that in many cases my opponent ends their turn with all of their mana untapped in the early game as playing a card or pumping it to do more damage could cost them their creature.
In the mirror match (vs other Blue-Black control) is where this deck has had the most difficulty over time. To try and improve performance in this matchup, I brought in Monastery Siege in an attempt to get better card selection and a faster Dig Through Time than my opponent. Game two onwards, I bring in Silumgar, the Drifting Death, Stain the Mind and Palace Siege. Silumgar gives an additional threat to attack my opponent's life total with, without giving my opponent's removal spells an additional target due to hexproof. Stain the Mind is used to target Dig Through Time unless you can guarantee you will hit a creature with it. One way of doing this is to spend 8 mana to return their Pearl Lake Ancient to their hand before using Stain to remove it. Palace Siege is usually used in Dragons mode to put a clock on the other player as well as provide a little recovery for my life total too.
