>>198062751. Ai-chan - She was the first truly succesful chuuba, and practically popularized the concept.
2. Eilene - While the Eilene project was primitive to begin with, her influence on the industry should not be understated, as she was one of the first.
3. Fubuki - Hololive's most subscribed channel for a very long time. It is in large part due to Fubuki's short meme videos, that chuubas gained popularity in the west
Honorable mentions go to Aqua the Queen of the Chinks, Coco the Queen of the EOPs, and Kaguya "Overnight Success" Luna
Out of fairness i would've mentioned some Nijis too, but i've never actively watched them, so i am not at liberty to rank them.