This deck looks powerful and well tuned. However, no Vampiric Tutor and no Strip Mine? Is it just the lack the physical cards or is there another reason not to play these?
Also, black decks naturally have a hard time interacting with artifacts and enchantments. But since you have access to some tutor effects, a single silverbullet could make a big difference. How about Karn Liberated, All Is Dust, Nevinyrral's Disk or Ulamog, the Ceaseless Hunger?

Emzed, thanks for the feedback! The only reason I don't have Strip Mine or Vampiric Tutor in here is because I don't own them. I would certainly replace Beseech the Queen with Vampiric Tutor if I get one in the future though :)

As for enchantment and artifact destruction, I used to have Unstable Obelisk and Scour from Existence in here. I found them too expensive for what they do though. I may consider adding Nevinyrral's Disk. I don't like the fact it comes into play tapped, but it may still be worth it. I also like All is Dust, but it doesn't help me out with artifacts since it only gets rid of colored permanents. Karn and Ulamog are also too expensive mana-wise (and Karn $$$-wise).

For the most part I've moved into acceptance that artifact and enchantment removal is a weakness of the deck and chosen to focus on Black's strengths as opposed to trying to compensate for its weaknesses. I don't know if that's the best approach though lol.

Crypt Ghast, Cabal Coffers, Black Market, Nykthos, Shrine to Nyx, Ashnod's Altar - are you sure you can't cast Ulamog? If there is any way to make it happen, he is certainly worth the effort.

Oh, another budget-friendly but great and flexible option for you would be Praetor's Grasp. It can get you stuff like Sol Ring (essentially a Sisay's Ring), Strip Mine, Animate Dead, Damnation, Demonic Tutor or Ulamog, the Ceaseless Hunger. If those are cards you can find in your playgroup, it's a really solid card.

Emzed, I like the look of Praetor's Grasp! Thanks for the suggestion :)

Emzed, I like the look of Praetor's Grasp! Thanks for the suggestion :)