The reason to try logging in to Citibank (for credit card accounts) is that it’s a hard website to log in to. If it works there, it’s likely to work almost everywhere.
Also try these websites, as some of them are harder than most, but not as hard as Citibank:
US Bank
Penfed
Capital One
Most other websites can be done by Chrome. It autofills the login/password when you navigate to the website. But it doesn’t do the above websites very well, because something unusual there prevents it from recognizing the login procedure correctly.