Become familiar with these saxophone types in this instrument family.
School bands, the sax quartet, wind ensembles, and jazz ensembles of varying size use these voices. Yes, there is the sopranino, the bass, and the C melody as well, but these are seldom used outside of saxophone ensembles or atypical compositions. (Who owns their personal alto clarinet? See what I mean?)
My experience with sopranino and bass is very little. I found both difficult to play, and believe they possess better potential as a toy and small vehicle respectively. Oh by the way, the Baritone page tells how to make a boat anchor out of a bari sax.