Holly

Holly is the daughter of Pete and Poppy's Twin sister. She appears in Sarah and the Book Series

Sarah
Holly, Poppy, and Anxelin first appear as New Babysitters in Sarah. Holly is chewing Gum and she is revealed to Babysit until Midnight.

Lost and Found Island: A New Babysitters Club Novel
Holly appears is when she and Poppy tell Anna to get away from Dakota's cauldron.

Return to Lost and Found Island
She appears again as an attendee at Carlos, Evie, Jay and Mal's welcome home party and one of the members of the Anti-Heroes Club. She reveals to Mal and the others that she wants to be good, possibly foreshadowing being transferred to Auradon Prep in the future.

Trivia

 * She was introduced with Poppy and Anxelin in a Scene of Sarah. They appear again in chapter three of Lost and Found Island: A New Babysitters Club Novel and the Trio appears once again in chapter 24 of Return to Lost and Found Island: A New Babysitters Club Novel