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