I've googled the question and come up with lists published by various companies but they always seem focused on those who are the most prevalent speakers, presenters or bloggers. Should I just assume they're the most prevalent for a reason or are there less outspoken leaders who have more insight and/or are working on really interesting problems?
I've been impressed by https://sqa.stackexchange.com/users/213/bj-rollison both in this community and when I've seen him present at conferences.
https://sqa.stackexchange.com/users/246/user246 is clearly the leader in our space her in Stack Exchange. Unfortunately they prefer to keep an air of mystery.