Let's get some predictions going! I'm a nerd and had read all the books prior to the show airing so I pretty much knew what was coming for the majority of the series. Now that the R+L=J theory has been proven, it's time to go on record with what we actually think will happen in the final 8 episodes.
Cersei - She has to die a horrible death, right? GoT fans have waited a long time for one of the best antagonists of all time to get what's coming to her. My guess is it's more poetic then grizzly and she is ultimately killed by Jamie as his betrayal could be the only thing that would ever actually wound her black heart.
Daenerys - Everything has been built up for her to be the savior and sit the iron throne and rule. That's not George RR Martin's style. She has shown hints of her fathers cruelty and a willingness to burn her enemies without much thought or consideration for wise council. I'm assuming she goes crazy as is her real birthright and ultimately has to be put down, likely by Jon
Snow Targaryen.
Samwell Tarley - He proves his worth to his brothers and ultimately replaces Jon as Lord Commander of the Nights Watch. It's been speculated he is George RR Martin's way of writing himself into the story. We could see a Neville Longbottom moment where he kills the Night King, earns the Sam the Slayer title he was given in jest and saves the realm.
Sansa rules the North. She's been the poster child for weakness through the series while all her siblings have risen to high levels of importance or badassness. We finally see her take a little initiative in season 7. Her suffering pays off as she is ultimately the reigning Stark in Winterfell and all the northern lords support her.
Jon Snow - this is hard to pin down. He was brought back to life to serve a greater purpose. It's either to ultimately sit the iron throne and rule, or its to sacrifice himself to save the realm likely by killing a mad Daenerys and dying in the process. If this happens, I wouldn't be shocked to see the monarchy dissolved and a ruling council installed with people like Sansa, Tyrion, Brienne, and Davos Seaworth sitting the council along with some other more fringe characters. Perhaps representatives from each of the 7 kingdoms. Yara or maybe even Theon from the Iron Islands as his character is given a full reconciliation.
The Hound - I'm thinking he survives and goes to farm in peace somewhere. This is just what I hope to happen. Or perhaps he dies sacrificing himself to save someone like Arya fully cementing their interesting relationship. He, of course, has to kill the Mountain first.
Grey Worm and Missandei live happily ever after together. Someone has to, right?
Sic Everyone.