Boss' PS-6 offers major and minor harmonies, pitch shift, detune and the Super Bend effect, which delivers pitch sweeps.
These are triggered by holding the pedal switch down or controlled, Whammy-style, by adding an expression pedal. The Pitch Shift function supports a variety of intervals, as does the set-by-key Harmony.
The balance knob sets the blend between dry and pitch-shifted signal, so you can, say, tastefully blend in an octave up for a 12-string effect.
A compact choice delivering a tasty range of musical pitch effects to your 'board.