Is there a list of how you can get different titles below yours username? I've only gotten one so far and I would like to get more

There is a thread you can look at right HERE that lists all the titles and how to obtain them. :)

Not an offical list I know of but if you go through all the achievements on the achievements page you will see ones that have Title: (whatever the title is) and you will get that title after gaining that achievement.

Since showed you which thread it is located I am going to lock this thread. Please try to check the sticky at the top of the forums for topics that might be able to help you with your question. Thank you! :)