Check the Internet Movie Database under Thundercats, it will give you a list of the voice actors. If you click on the individual's names, it will send you to a bio page where you can learn a bit about them, but they do withhold the actors addresses.
http://www.imdb.com/title/tt0088631/fullcredits#castOh thanks! IMDB.com was the first place I checked but FOR SOME REASON whatever I clicked only had Lion-o's voice. Weird!
I don't EVER write to an actor's home address to obtain an autographed photo... ALWAYS their fan mail address. Been collecting autographed items since early 90's. I've sold some of my collection throughout the years but hold on to my favorites like Larry's. I'll do some digging for fan mail addresses on these actors.
Thanks again!