The four patron trolls: Kanaya (the Optimist), Terezi (the Cynic), Karkat (the Realist) and Vriska (the Apathetic). Tavros (though not a patron troll) fits in as Conflicted.
The Midnight Crew: Spades Slick (the Cynic), Diamonds Droog (the Realist), Clubs Deuce (the Optimist) and Hearts Boxcar (the Apathetic).
And Aradia manages to hit all four points at various times throughout the series. Specifically: alive!Aradia (the Optimist), ghost!Aradia (the Apathetic), Aradiabot (the Cynic), and god-tier!Aradia (the Realist).
The Lizzie Bennet Diaries: The protagonist Lizzie (either the Conflicted or the Realist), Jane (the Optimist), Charlotte (the Cynic), and Lydia (the Apathetic).