Hi,
I’ve found a site that can prove extremely useful for many of us here.
The application shows the name of a chord you mark on the neck diagram and vice-versa, it can show you all possible fingerings for a chord you’re looking for. There is quite an amount of chord theory available, and even some quizzes. I find it very useful, but also fun to use (for naming chords and showing a named chord diagram use the first two icons on the upper menu bar).
Enjoy!
I have been using the Oolimo app on my phone for around a year now and it is great for figuring out chords and for seeing alternative fingerings for a given chord.
I too have enjoyed the various chord quizzes and the use of a fret board interface with the ability to show both note names or intervals has really helped improve my understanding of music theory.