The CAGED system uses C, A, G, E, and D open position chord shapes to become movable shapes using barre chords. You can play each shape for any major chord. The pattern of shapes always follows the order of CAGED so it becomes a very valuable way to remember chord positions in any key up and down the neck. This logic applies to open tunings as well. First learning this in standard tuning has helped me find chords in many different tunings with some adaptations.
Here are the shapes:
