One of the best ways to become familiar with chords in all keys is to take a simple progression and transpose it to all the keys. This may be slow at first, but the more you do it, the easier it gets. Here are some to start with. Remember to practice them in different ways, e.g. as strummed chords and fingerpicked as arpeggios.
The scale tone chords studied so far involve the placement of two notes (separated by an interval of a third) above a root note. This method of building scale tone chords can be extended by adding another note of a third interval.
Here are the scale tone 7ths in C major played in root position.
The following example contains all seven scale tone 7ths in C major. The progression is I IV VII III VI II V I. The shapes used here are all close together on the fretboard. This makes them easy to play and results in a smoother sound than moving up and down one string to find the root notes of the chords.