ModTools helps forum moderators verify spam accounts easier. Check usernames, email addresses, and IP addresses against the StopForumSpam service; and verify that emails aren't disposable addresses. This allows you to quickly and easily verify fake accounts prior to banning them.
You can also check to see if email addresses appear on the Block-Disposable-Email list.
If you use a reliable service that you'd like to see added send a request from the Help menu.