So, I just re-watched the Hardhome episode with the woman (her first time through watching GoT), and the amount of foreshadowing is ridiculous.
Most hilarious: Sam totally convinces Ollie to murder Snow. He had a conversation about how "a man must, sometimes do what he thinks is right, even if others don't see it that way" (paraphrasing), after he is asked if he thinks Jon saving the wildlings is right. Ollie agrees, sort of (a man, Ollie, has to do what he thinks is right [murder Jon]).
Also, one of the wildling elders talks about the myth of "ice spiders as big as hounds." They're talked about in the books...so season 7 or 8 giant cgi spiders?
There were a few others, but typing on my phone is slow...so, re-watch that episode again, ladies.