We all saw in LotR trilogy that many of the actors from that series never really worked again in anything high profile. There were exceptions such as Viggo Mortenson and Ian Mckellan.
I see only a few actors having their career furthered by the GoT series.
That's why Kit Harington and Emilia Clarke have gone for action and romance films over the last 3 or so years, so they can show their ranges. Richard Madden was typecast when he first left the show, but I think he's currently on a police show for BBC. Natalie Dormer was in the Hunger Games with Gwendolyn Christie, who was also in the last 2 Star Wars movies. Iwan Rheon was on one of those Marvel TV shows, but it got canceled before the season finished airing. The guy who plays Edmure Tully gets typecast in period dramas. The older actors, almost all are famous in British film, if not internationally.