Golgari - Witherbloom Pest (Modern)

The main goal of this deck is to drain opponents with on-death creatures effects.
The deadliest combos use any of following cards in addition with Plumb the Forbidden :

• Bastion of Remembrance
• Witherbloom Apprentice
• some Pests

The demons such as Daemogoth Titan and Daemogoth Woe-Eater are mostly used in order to be sacrificed with Tend the Pests, as a combo feeder.
The rest of the deck is focused on board control and token generation (Sedgemoor Witch + all other spells).

The sideboard allows the deck to focus on lifegain (with Prosperous Inkeeper) + creatures taking advantage of that (Callous Bloodmage), or token mecanics (
Blex, Vexing Pest // Search for Blex and Hunt for Specimens).

Future tests will use Professor Onyx and The Meathook Massacre. Vito, Thorn of the Dusk Rose may be added (acting like an additional Dina, Soul Steeper effect).

EDIT:
In fact, Plumb the Forbidden can be countered, but the additional cost of sacrificing creatures can't be prevented by opponent, and copies are not blocked by a counterspell.
X sacrified creatures will cause X Bastion of Remembrance death triggers (for 1 on board), and then casting the spell and all copies will trigger X+1 times Witherbloom Apprentice and/or X+1 Sedgemoor Witch. Adding a Dina, Soul Steeper on board will cause a X damages to opponent on Bastion of Remembrance (with additional triggers if Pests were sacrified), and X+1 damages on Witherbloom Apprentice triggers.
If the Prosperous Inkeeper is added to the main deck, it will also trigger on the X+1 Sedgemoor Witch, causing X+1 Dina, Soul Steeper triggers.

After several tests, it appears that sacrificing between 4 and 6 creatures (Pests, most of the time) will end the game.