Now bring in Harry Potter, Austin Powers & Doctor Evil, Mobius (Matrix), Mordecai & Rigby, Power Puff Girls, Daffy Duck, Godzilla, Emmet/Lucy (Lego Movie), It, Gremlins, Beetlejuice, Willy Wonka, Freddy Kruger, Omi (Xiaolin Showdown), Ed, Edd n' Eddy, Dexter Lab, Courage the Cowardly Dog, Grim Reaper and Mandy (Billy & Mandy), Samurai Jack & Aku, Yakko, Wacko and Dot, We Bare Bears, Dr Mrs Girlfriend the Monarch (Venture Bros), Buddy Hobbs (Elf), The Mask, Rorschach & Dr Manhattan (Watchmen), Static Shock, Annabelle and Raven & Cyborg from Teen Titans GO.
edit: I think that covers most of the WB grounds. I'm sure there are more reps people would want from certain universes.