Solution to Rectangles

Each row of rectangles depicts a set of people or characters characters in a minimalist style. The sets are:

The Beatles (in the Sgt. Pepper's album cover outfits)
John Lennon, Ringo Starr, Paul McCartney, George Harrison
* = Ringo

My Little Pony: Friendship is Magic
Twilight Sparkle, Fluttershy, Applejack, Rainbow Dash, Rarity, Pinkie Pie
* = Applejack

Pokemon (TV)
Jessie, James, Meowth, Brock, Ash, Misty, Pikachu
* = Misty

Justice League (TV)
Martian Man Hunter, Green Lantern, Wonder Woman, Superman, Batman, Flash, Hawkgirl
* = Batman

The Addams Family
Wednesday, Gomez, Morticia, Pugsley, Thing, Lurch
* = Lurch

Minecraft
"Steve" (the default player skin), Skeleton, Enderman, Zombie, Creeper, Slime, Spider
* = Enderman

The Wizard of Oz
Scarecrow, Tin Man, Toto, Dorothy Gale, Cowardly Lion
* = Scarecrow

Taking the first letters of the starred chracters' names gives the answer RAMBLES.