[Primer] +Manaless Dredge+

[Echelon]

Not having Bridges probably means you may have to split your combo over 2 turns (although recurring Bloodghasts mid-combo might give you enough creatures to finish it entirely).

Let's say Kelpie is the only creature we have on the field when we DR it and with our last dredge we get back a Dakmor Salvage. If we manage to get 3 Bloodghast in our yard and/or Narcomoeba on the field whilst dredging that'd be enough to complete the combo without any help from Bridge from Below. You sacrifice Kelpie + 2 creatures (1 creature + Kelpie left on the field) to DR Flayer and then sacrifice Flayer, Kelpie and the last creature to cast the third DR, targeting Grave-Troll. Seems reasonable.

You could also switch out the 3 Vengeful Pharaoh and a River Kelpie for 4 Bridge from Below. 20 creatures, Bridges and a combo finish all in one list.