Aaron Smith
Envisage Audio
Auto-Tune is the only one I have experience with on this, but it works great for tuning bass, as long as you're using "Graphical" mode. It even has a "Bass Inst" input field when you're setting up the tracking controls. Also, I've found that with the bass especially (in some cases), I need to dial forward the "Tracking" knob towards the "Choosy" side (which defaults to 50% between "Relaxed" and "Choosy"). Otherwise, if there are harmonics ringing in the bass tone, they can confuse Auto-Tune's ability to sense the pitch.