Yes, I believe I've read almost every Berenstain Bear book ever made. And I've seen them go through changes and new characters have been added ever since The Big Honey Hunt.
It started out with just Papa Bear, Mamma Bear, and Small Bear. Then later, Sister Bear was added and Small Bear became Brother Bear. (I guess Small Bear was his nickname back then.)
Then, a bunch of supporting characters were created in the bear filled land of Bear Country. Farmer Ben, Mrs. Ben, Actual Factual Bear, Great Natural Bear, Bigpaw, Teacher Jane, Grizzly Gramps and Grandma, Cousin Freddy, Snuff the Hound Dog, Too Tall Grizzly, Mayor Honeypot, Raffish Ralph, and Weasel McGreed. And some cartoon series and specials were finally made about this wonderful book series.
Just recently, Mamma Bear had a third child. A baby girl named Honey Bear. Also Brother Bear is now dealing with preteen stuff. It just shows how long The Berenstain Bears have been going on. I salute Stan for the many books he and his family have brought out and hopefully his family will continue the legacy.