There are 12 attractions at Magic Kingdom we rate as "Not To Be Missed":

Not To Be Missed at Magic Kingdom
Adventureland Pirates of the Caribbean
Fantasyland Mickey's PhilharMagic
Peter Pan's Flight
The Many Adventures of Winnie the Pooh
Under the Sea ~ Journey of the Little Mermaid
Frontierland Big Thunder Mountain Railroad
Splash Mountain
Liberty Square The Haunted Mansion
Main Street, U.S.A. Celebrate the Magic
Main Street Electrical Parade
Wishes Nighttime Spectacular
Tomorrowland Space Mountain

Not To Be Missed Attractions at Other Parks