Hippowdon X is fun with Blissey, because he and Hippowdon RR do the same thing but the X can help to disrupt more.
Also Pluspowers, Buck's, etc. and perhaps some healing tech (Blissey PT)
Vulpix PT is a great starter with blissey so you can build up some energy in discard. If you're playing the weavile variant, sableye is good because it can discard energy with Volkner's or Felicietie's, and it can also earn you a donk if you're lucky.