I have a lot of the experience with the Instagram API....I can do this. I can extract email wherever it's part of the user profile, but obviously not all people have emails in their public profile. They don't have a way to search for people that have more than a certain number of followers, but I can have the software crawl through the profiles of anyone that winds up with a popular post, and then record the username and email (if available) of anyone that pops up with a popular image that has more than 20K followers.
Edit:
Actually I just found an easier way for my bot to do it: I can have it scrape usernames from Google results from queries like the following, and then have it visit the IG profiles in the results and extract the info you want:
Code:
site:instagram.com posts 20K followers email -inurl:explore -inurl:/p
and then increment, so make it "21K", "22K" etc. Let me know if you want me to do it. Check out the results for that query, and you'll see exactly what you want. I even have unlimited proxies that I can scrape the results with. I can pull out probably a couple hundred thousand accounts pretty quick.