The GuitarChords 247 iPhone App has 42 000 chords and a powerful search which gives you all the possible variations  commonly used chords without unnecessary bells and whistles to complicate the process.  I use it when I can’t find the chords I need and it’s right at my fingertips.

The App is available here – https://itunes.apple.com/us/app/guitarchords247/id391091651