The Little Monsters was published by Golden Key from late 1964 until it's last issue, #45, in 1978. I do not remember it at all from when it was being published. My first introduction to the characters happened when I discovered the books in the old comic sections of comic book shops.
The stories and humor are not very innovative; but the characters actually debuted as a back up story in The Three Stooges #17, in May 1964, before The Munsters or Addams Family TV shows premiered in the fall of 1964.
art @ Golden Key