Two

Salt and Pepper
Laurel and Hardy
Bonnie and Clyde
Harmony and Melody
Rhythm and Rhyme
Barnes and Noble
Ebony and Ivory
Bert and Ernie
Shoes and Socks
Bacon and Eggs
Shrimp and Grits
Ben and Jerry
Rain and a Good Book
Ruth and Naomi
Yin and Yang
Cheese on Pizza

Michelle and Sandra...

Sandra and Michelle.