Augmented and diminished chords are not as common as major or minor chords, but it is still important to learn them. They occur in many pieces of music as a way of creating tension, before resolving to either a major or minor chord. Here are some examples demonstrating these chords.
C+
Co
Here is an example which makes use of arpeggios of all four types of triads – major, minor, augmented and diminished.