5) Littlefinger
With all the scheming and double-crossing that’s constantly going on, we hardly ever know the true intentions of the inhabitants of Westeros and Essos. Littlefinger to his credit at least made his intentions clear at the close of season six: turns out he has his eye on the Iron Throne itself, and it would seem he’s planned out exactly how to get there.
It’s an ambitious scheme for a minor lord with no blood connection to any major house. But who are we to doubt Petyr Baelish, who has gotten precisely what he’s wanted every step of the way so far? Like Varys, Littlefinger is a born plotter, and a hugely successful one at that. We don’t know much about his long-term vision yet, but you just know he has one, and judging by his achievements so far you can imagine he’ll get at least close to realizing it.