In the modern flute family there is a C flute(the most common one), a piccolo which sounds an ocatve higher, an alto flute in the key of G (so a fourth lower then the c flute), and a bass flute which is an octave lower then the c flute.
Stringed instrument have different methods to play them. The violin family has 4 instruments played by a bow, the piano is a percution stringed insturemt, the classical guitar is another stringed...