Lily Munster. Why? Why not! She took good care of Eddie & made sure he always had his Woof-Woof at bedtime. She was masterful in keeping Herman out of trouble because of his own naive sweet natured stupidity.* And she was tolerant of crazy Grandpa and that hideous Marilyn.
* Lily, to me, is the prototype for Marge Simpson to Herman's Homer. Deep thoughts.