Disallow Username Plugin?

Howdy!

I’ve been looking to see if there is a way (or plugin) that will allow the administrator to disallow certain usernames from being taken when a new person registers on my WordPress site?

There are certain names that I need to be sure are not registered as they will be used for future events on the site as well as “special guests.”

I know in phpBB they have a feature where the Administrator types in a name to be “held” and anyone that tries to register with that name is given a message that the name is not available and that they should choose a new name.

As it is now, I need to disallow close to 300 names and know I could just create new users with those names, but that means adding email addresses, passwords, and other info that will take up too much time.

Is there a simple way to just block certain names?

Thanks in advance!
Bill