You've learned four different barre formations: The E barre, A barre, E Minor barre, and the A Minor barre. By making a very slight change to each of those formations you can play even more chords. Each Major and Minor barre formation can easily have a Major 6th or a (Dominant) 7th added to the chord anywhere up and down the fretboard.
Figure 8-1 shows the standard E barre formation, the E barre with an added 6th, and the E barre with an added dominant 7th. Each formation is shown with the index finger in the 5th fret and the resulting chords are E (major), E6, and E7. To form the 6th or the 7th chord, you simply move your pinky finger (numbered as 4) from the 3rd string and place it in the relevant fret (as shown) on your 5th string.
PLEASE NOTE THAT THE IMAGES BELOW ARE NOT MIRRORED. THEY DEPICT THE FRETBOARD OF A RIGHT-HANDED GUITAR STANDING UP.
Figure 8-2 shows the standard A barre formation, the A barre with an added 6th, and the A barre with an added dominant 7th. Each formation is shown with the index finger in the 5th fret and the resulting chords are D (major), D6, and D7. To form the 6th you allow your ring finger (marked as 3) to barre the bottom (6th) string while it also barres the 3rd, 4th, and 5th strings. To form the 7th, you simply add your pinky finger (marked as 4) to the 6th formation but one fret higher.
Figure 8-3 is a chart showing all of the chords available in the first 12 frets by using all four barre chords you have learned. The graduated color code indicates where chords are repeated from one barre formation to another. The 6th and 7th formations for the E barre and the A barre shown above can also be used in any location on your fretboard of course, and they - like the standard barre formations - do appear in more than one location.
For instance, if you place an E barre formation with your index finger in the 7th fret (medium green) you will get a B chord. You can also play a B chord by placing an A barre formation with your index finger in the 2nd fret (medium green). The B minor chord can be formed by placing the E minor barre formation in the 7th fret, or, by using the A minor barre formation in the 2nd fret.
You can see that instead of sliding or moving up to the 10th fret to play a D chord with the E barre formation, we can play it by using an A barre formation in the 5th fret. So, let's imagine we want to change from an A chord to a D chord. We can simply play an E barre in the 5th fret and change to an A barre in that same fret. That makes chord changes much quicker and easier to perform. You'll appreciate that more when we look at Common Chord Progressions, Song Patterns, and Fretboard Patterns in later lessons.
You should practice the four different barre formations along with the added 6ths and 7ths and familiarize yourself with the chords they produce as you move them up and down the fretboard. There are several patterns and relationships regarding their locations in respect to each other which will help you remember their location on the fretboard. We will look at some of those relationships and patterns in the next lesson.