> Besides Sean Bean — who was far from A-list — how many of the Games of Thrones cast were well-known?

None A-list, obviously, but (in no particular order) Lena Headey, Iain Glenn, Natalie Dormer, Peter Dinklage, Nicolaj Coster-Waldau, & Charles Dance, arguably.

Game of Thrones was packed with a murderer's row of character actors from British stage and screen.

Yeah, it probably explains why a lot of Americans had not heard about them.

Lena headey will always be on my A-list because of terminator:scc

Ser Bronn spent seven weeks at the UK chart number one, bestselling single of 1995, had an album that went 6x platinum and another that went 4x platinum.

https://en.wikipedia.org/wiki/Robson_%26_Jerome

https://youtube.com/watch?v=r5V8ecsrxeY

Ian McShane was Lovejoy on British TV for 8 years and after GoT has been in John Wick; https://en.wikipedia.org/wiki/Ian_McShane

Ian McShane was in exactly as many GoT episodes as Ed Shireen: one. He’s hardly a star of the show.

Ian McShane was a major Cast member in HBO’s deadwood like 20 years ago

I haven't seen GoT but Jason Momoa was already a decently well known name before that show, he has been in other things and he is so unique, once you've seen him you never forget him.

Famous for Stargate Atlantis? He was great in that but not well known.

He was on Baywatch and North Shore before that.

Famous is probably the wrong word, but he was known in the TV industry. Basically if you were adding an "exotic beefcake" to an ensemble cast someone would suggest Jason Momoa.

Good question, Like you mentioned, Sean Bean(very well known from goldeneye and LOTR), Lena Hedley was known for her terminator work, Peter Dinklage(Elf, Nip/Tuck), and lets not forget Natalie Dormer(playing Anne Boylen on the tudors, a popular TV series a few years before GOT). Basically if you watched popular scifi/historical shows/movies these characters(some) were well known.