https://www.oolimo.de/index.php

Another cool site for visualizing the fretboard.

Oolimo covers the basics and theory with many good articles on the subject. They review the basic chord types like CAGED. And, there are chord progressions suggestions where you can see how progressions are used in different songs.

Finally, you can test yourself in their quizzes section on intervals, putting the fretboards in their correct positions, and more.

Features: - Chord Finder - Chord Chart - Chord Analyzer - Chord Progressions - Quizzes