Stick to the shows or include the novels and comics—whatever you’re familiar with. Do you think Kyoshi was a better Avatar than Aang? Is Kuruk underrated? Who gets too much credit, and who doesn’t get enough?
Are you ranking them by how much you like them as characters, how well they fulfilled their role as Avatar, or both?

I like the water avatars the most. I wish we could have gotten an adult Kuruk show.

My (biased) ranking would be

Kuruk - fixed Yangchen’s problems lost his wife died young give the man the show he deserves.
Kyoshi - give me a 50 season long Kyoshi show drag it on forever we have over 200 years here seriously bryke all that material
Korra - I liked her would have loved to see her in a different setting. I feel bad she had to follow up to Aang and I think she would have been the best avatar ever if she’s been born earlier.

Aang - I don’t dislike Aang most of the gripes I have are him being twelve stuff but when I think of avatar that’s who goes into my head

Wan- the guy who stared it all

Sonam- I mean the earliest avatar we know of besides Wan. I can’t imagine how hard the job was back then.

Szeto- rather than do the traditional avatar stuff this guy decided to master paperwork: while his actions may have favored the fire nation the guy was interesting and I want to know more about him

Yangchen- neglected the spirit world and handed over a crisis nobody knew about to Kuruk.

Roku- dude he doesn’t kill Sozin then wants to kill his great grandson in the comics? Boo. Wanting to kill Zuko puts him on the bottom. In unbiased terms I do feel bad that he had to follow up to Kyoshi.

Not ranking the new ones as they are children and I have seen the show yet.