). There is a tool that checks the list of usernames and tells which ones are available to register a new account with, just google.
Just scrape all popular/semi-popular hashtags and try to find those hashtags as usernames and see if they are available (hard task, but maybe you will find a great username
No one can do that since instagram changes the token after 90 requests so that's why they do 1 by 1, you need to make a bot that checks it on their website like this:
