Find new chords in any tuning or capo placement (including partial capos).
Chord Hacker takes the setup into account, tries hundreds of chord shapes/positions, and picks out every result that actually forms a chord. From there it throws out the chords that aren't in the specified key - that way they sound decent together. Switching keys in a song is possible, but the change should be deliberate.

Feel free to make suggestions - please rate this as well - and now go make music with a unique sound!