@blindtherapy we played a lot of Delve spells in decks that didn't use the graveyard other than that. Also, extra DTT, Cruise would make excellent FoW fodder. I don't know if this reasoning works with Breach. The cards in your graveyard aren't just numbers, you need good stuff there too.
@vaughnbros that's where I don't think I agree. Casting DTT makes Breach worse by 2 castings. So imagine you have 7 cards in our GY where 1 is Ancestral. You can cast it twice off Breach or 0 times if you find Breach with DTT.
The real question is: would you rather resolve DTT now for UU or 2 Ancestrals later for 1RUU?
When Soul-Guid Lantern enters the battlefield, exile target card from a graveyard.
T, Sacrifice Soul-Guid Lantern: Exile each opponent's graveyard.
1, T, Soul-Guid Lantern: Draw a card.
Although 1 mana more expensive, this has a lot of advantages over Tormod's Crypt. It does something right away and also doesn't target the opponent to exile the whole graveyard (oh, and can cycle if needed). I really like it.
This doesn't work well with either Chain of Vapor or Teferi but kinda works with PO, meaning that you can target this with PO this just to sacrifice it. I don't know it this makes it better than Night's Whisper in PO lists that want it, but I don't even see PO with Whisper right now, so idk. And with Underworld Breach coming, I doubt black will be the better color for those kinds of decks right now.