Game of Thrones has quite a list of characters, with many being added every season and a fairly good number being killed. The sheer number of characters can be overwhelming, as with their house affiliations and even knowing if they are dead or alive. This periodic table by Christian Petersen ought to make up for that, letting you see characters arranged in a way to inform you of their names, the houses they belong to, and if they are dead or alive.
This one contains spoilers from the books, so proceed at your own peril; making it more of A Song of Ice and Fire periodic table than a Game of Thrones one. The artist is currently working on a spoiler-free version for the show watchers. The print costs $20 on Etsy.