Duals

Most Duals will probably be opposites(eg. antonyms) but you shouldn't limit yourself to just them.

Salt	Pepper
Odd	Even
Up	Down
Left	Right
Arrive	Depart
Big	Small
Tweedledum	Tweedledee	Through the Looking-Glass and what Alice Found There
Statler	Waldorf	Muppet Show
Positive	Negative
Day	Night
Black	White
Happy	Sad
In	Out
Grin	Grim	:)  :(
Click	Clack	NPR Car Talk (The Tappet Brothers)
Bert	Ernie	Sesame Street
Bill	Ben	Flower Pot Men
Jack	Jill	from nursery rhyme
Yin	Yang
Boss	Minion
Tom	Jerry
Vladimir	Estragon	Waiting for Godot
Rosencrantz	Guildenstern	Hamlet
Thunder	Lightning	Very Very Frightening
Wayne	Garth	Excellent!
Bill	Ted	Totally
Mulder	Scully
Jake	Elwood	Blues Brothers
Beavis	Butthead	90s-Era MTV
Hammer	Sickle	Communism
Tick	Tock
Sweet	Sour
Heaven	Hell
Jekyll	Hyde	Strange Case
Bull	Bear	Stock Market
Adam	Eve
Ben	Jerry	Ice Cream
Zero	One	Binary
Laurel	Hardy
Abbott	Costello
Bacon (or Ham)	Eggs
Bread	Butter
Cat	Mouse
Hamilton	Burr
Hardcastle	McCormick
Charm	Strange
Dipper	Mabel	Gravity Falls
Frog	Toad	Frog and Toad
Rick	Morty	Rick and Morty
Phobos	Deimos	Mars moons
Null	Void
Mario	Luigi
Scylla	Charybdis	Sea monsters in Greek mythology
Hammer	Chisel
Romeo	Juliet
Crockett	Tubbs	Partners from Miami Vice. Alternatively "Sonny & Rico".