The options for backs & side tonewoods are the most extensive in luthiery, however I usually build with a select few.
Rosewoods ~
Rosewood like:
~ Bloodwood (Brosimum rubescens) Deep red in colour. Not a true rosewood but possessing a similar tone.
Ebony:
Acacias:
Myrtles:
Walnuts:
Mahoganies:
Maples:
I will of course build with suitable tonewoods not listed here (More species are listed here). I can also use any wood that the customer provides, as long as it is suitable, stable and will not in any way diminish the final product.