Here are some of my personal recommendations for some great TV if you're looking for something to fill the hole left by Game of Thrones!
Vikings - This series starts off humble in budget and scope but quickly opens up into one of my favourite shows.
Fortitude - The first season is truly wonderful. Great mystery thriller set in Arctic Norway. Haven't seen season 2.
Boardwalk Empire - This is just TV masterpiece set in prohibition era US.
The Last Kingdom - Another show about vikings but a different beast to Vikings. Worth it.