Cersei - 90%
Jaime - 60%
Euron - 50% (think he may be the big bad)
Dany - 40% (or she may be the final big bad)
Jon - 20% (survives to take on either Euron or Dany in the final episode)
Arya- 40% (wouldn't be surprised if she is taken down for shock value from either Euron or Dany). Her death would be the worst.
Sandor - 90% (injured by Gregor, finished off by either Euron or Arya, the later due to mercy)
Gregor - 90% (almost certain)
Sansa - 05%
Grey Worm - 70% (last of Dany's true inner circle, Dany's armies likely collapse and he's also the 'character' of all of them).
Varys - 95% (due to prophecy)
Brienne - 05%, potentially she follows Jaime? Doubtful.
Yara - 10%
Qyburn - 50%, could see him swapping to Euron, possibly with Gregor?