I have guitar toolkit as well. It's tuner is better than any other tuner I own and you can look for any chord by letter or reverse lookup. It can play the chords to you as well. It's nice to have if you play or play with others who play guitar, mandolin, banjo, etc. It has the tuner presets for many stringed instruments or just tune chromatic, and you can change the tuner reference pitch. It also has a playable fretboard that you can pick at or set to show scales in all the different forms such as major, minor, pentatonic, etc. It has a nice metronome too. Out of all the apps I've bought it is the best by a mile.
It has support for 6 and 12 string guitar, 4,5, and 6 string bass, banjo, mandolin, and ukulele.