|Not just tops and backs, but all the wood elements on your instrument offer a choice in species. Necks can be of maple (my preference on violin-family instruments and some banjos) or mahogany (my choice on most guitars and some banjos)
or even alternative woods. For fretboards, I prefer the density and wear properties of ebony, but I also use rosewood, wenge, ziricote, and others. I also prefer ebony for bridges, though other choices sometimes make more aesthetic
sense. Headplates, chinrests, and violin tuning pegs are almost purely chosen by looks, rather than function, and the choices there are multitude.