Aw man forgot about littlefinger!
Freys
This doesn't really count as being on Arya's list but I loved the way she named Jaqen H'ghar and got him to do all that killing for her. She was young back then so it shows the brains behind the killing machine.
Hey up there! She didn't kill Joffrey! Olenna did how could you forget Olenna's death scene with Jaime?
Freys was so fire
Freys
Walder Frey
Frey's leave the one wolf and the sheeps are never safe
House Frey!
Meryn Trant, poetic justice is her bloody signature!