I got you

The Powerpuff girls. The Three Musketeers. Ed, Edd and Eddy. The Warriors Three. Your mom and her two thighs. Hell, Chandler, Joey and Ross.

School, grades and depression.

Shenzi Banzai and Ed

Ben, Gwen and Kevin. Courage, wisdom and power.

I have no idea who any of those people are.

It's a quartet. You forgot the Stig.

The girls from FRIENDS.

Moe, Larry, and Curly

Sam, dean & Cass