GERB: no cooperation with BSP under any form; preferred partners: PP and DB
PP: no cooperation with GERB/DPS, until their corrupt leaders resign and/or are jailed. So no cooperation with GERB/DPS. Preferred partners: DB
BSP: can't think of any; Preferred partners: Uh... come back to me later
ITN: no cooperation with GERB/DPS. No support for any cabinet which includes Petkov (PP) as minister/PM; Preferred partners: PP and DB
DPS: no cooperation with DB. Preferred partners: GERB, to a lesser extent BSP;
DB: no cooperation with GERB/DPS. No support for any cabinet under BSP mandate or containing former Communist secret service operatives. Preferred partners: PP
So there are two coalitions that could theoretically not breach the red lines - GERB + DPS and PP + BSP + ITN + DB. The first coalition obviously won't get a majority, and the second coalition (without PP) has been "tried" two times (who knows, maybe third time's the charm?)
