I've been experimenting with 8-Rack variants for several years and this is my current brew. Splashing red adds some good sideboard cards and additional pressure in the form of direct damage, giving your opponent less outs.
The core of the deck is one of the more common 8-Rack shells: four copies of The Rack and four copies of Shrieking Affliction. I'm running the variant with Ensnaring Bridge and no creatures.
I use Inquisition of Kozilek and Blackmail for selective discard. I like Blackmail over Thoughtseize because it can hit anything (including land) late game and doesn't cost life (it is surprising how often this comes down to a race). Raven's Crime gives recursive discard, giving any land the potential to become a discard spell. Blightning is the hammer for the deck, dealing 3 damage to their face and causing them to discard 2 cards.
Funeral Charm is a utility oriented, instant speed discard spell. Late game, this allows you to force a discard at the end of their draw step. The +2/-1 function can also obnoxious creatures like Dark Confidant (which draws additional cards), Signal Pest (which can swing past my bridge and attach Cranial Plating), and Noble Hierarch (another creature that can swing past bridge, as well as providing mana).
Rix Maadi, Dungeon Palace is a source of controlled, constant discard that is hard to remove. This also keeps my hand size down to keep bridge active. Liliana of the Veil has the same function, but also clears out creatures (even bogles). If left unchecked, you can also destroy their board. Smallpox basically hits all of Lilana's modes at once, plus destroys land.
I've decided to include Fatal Push, since it is an efficient creature removal tool that should work great in the early game, as well as Dreadbore, which removes planeswalkers in addition to creatures.
I include one copy of Syphon Life as a source of repetitive damage and life gain, helpful when racing against burn style decks, and keeping the damage flowing after they Engineered Explosives for 1. I also include two copies of Surgical Extraction in my main board, because there is always something to remove. At worst, you thin out some fetch lands or early creatures and mess up their curve. At best, you hit a tron piece, a Snapcaster Mage target (Surgical IS an instant with no mana cost), or a copy of one of their finishers when they assume they'll draw another later.
I have some odd sideboard cards, but I feel like they all serve a purpose. Crumble to Dust is my step up from Surgical Extraction for tron and valakut style decks. Pithing Needle usually shuts down artifact based removal (like Engineered Explosives or planeswalkers. Rakdos Charm removes graveyards, artifacts (especially Chalice of the Void on 1), and punishes players for building up a board of creatuers while they look for something to remove my bridge. Kolaghan's Command can provide creature removal or artifact removal while also forcing a discard. Shadow of Doubt slows down ramp, shuts down Scapeshift and Chord of Calling. Bontu's Last Reckoning is a cheap board wipe. Shattering Spree blows up lots of artifacts. Tainted Remedy is mostly to prevent infinite life from Melira, but can also make creatures like Thragtusk, Kitchen Finks, and Siege Rhino less playable. Ricochet Trap is mainly a deterrent for Hurkyl's Recall.
