Non-adjacent colors can cooperate very effectively, and their occasional dalliances are very spicy.
Golgari
Green Black
Golgari and Lenticular Design by Alex Ullman
Designing for Golgari by Mark Rosewater
Life and Death by Mark Rosewater
Simic
Blue Green
Improving Upon Nature by Mark Rosewater
Boros
White Red
Designing for Boros by Mark Rosewater
Color Pie Friday: The Philosophy of Red/White by Sarpadian Empires Vol. VIII
Disorderly Conduct by Mark Rosewater
Izzet
Red Blue
Beyond Izzet: Examining the Red/Blue Archetype by Seth Weinstein
Designing for Izzet by Mark Rosewater
Creative Differences by Mark Rosewater
U/R Izzet Philosophy, Strengths, and Weaknesses by The Mana Source
Luis Scott-Vargas drafts blue-red in this video of the Hour of Devastation format.
As Foretold Turns
This deck uses a number of different cards that allow you to take an extra turn.
Orzhov
Black White
Playing By Their Own Rules by Mark Rosewater