Yet Another Mystery Theme V: The Mystery Theme Strikes Back by VaccaD

Question 12

To WHAT GROUP do all the other questions in this quiz allude? As a hint: the first question refers to the only constant member of the group, the next seven to the other current members, the ninth to a former long-time member, and the last two to former members for only very brief periods.

LUCKY CHARMS MARSHMALLOW BITS (hearts, shooting stars, horseshoes, clovers, blue moons, rainbows, balloons, hourglasses, diamonds, whales, pine trees)