Here's a list of the most common colors that are often repeated in each model kit from Bandai. The Letter-Number code enclosed in parenthesis are its product reference no. for easier look up.
White (C1)
Black (C2)
Red (C3)
Yellow (C4)
Blue (C5)
Dull Grey (C11)
Neutral Grey (C13)
Navy Blue (C14)
Mahogany (C42)
Dark Iron (C28)
Sky Blue (C34)
Clear (C46)
Clear Red (C47)
Clear Yellow (C48)
Clear Orange (C49)
Yellow Orange (C58)
Pink (C63)
Indy Blue (C65)
Daytona Green (C66)
Purple (C67)
Monza Red (C68)
Midnight Blue (C71)
Medium Blue (C72)
Cyan?/Shine Red (C79)
Cobalt Blue (C80)
Tire Black (C137)
Clear Green (C138)
Fluorescent Yellow (C172)
Fluorescent Orange (C173)
Light Blue (C323)
I have to point out however that I'm working from memory here and I haven't really correlated it with the actual color guides. When making this list it was more of a "That sounds familiar" type of selection process. *snicker*