The Angry Beavers is a good show for all ages. The Angry Beavers has clean language. I know that some classic Nickelodeon cartoons include some adult humor. The Angry Beavers is a good show for all ages (I'd say all ages 5 and up).
You can watch all episodes there
You can watch all the old episodes of Fringe on ovguide.com
You can watch it on youtube but I don't know if that website has all of them but I did see all of the beast episodes but not beast plus episodes
Yes you can watch all previous episodes on the CW.com
youtube.com. But not all the episodes are dubbed :(
All That is no longer on the air.
You can watch all the episodes for free at Funimation.com
The first episode was called Born To Be Beavers/Up All Night. The last episode was called Specs Appeal/Things That Go Hook in the Night.
hulu.com has all full length episodes
you can find all episodes on narutoget.com
You can watch some episodes on Nickelodeon's website, they change them periodically. Also, YTV.com has a few episodes.