Augmented chords
Stretch the fifth of a major chord up by a semitone and the result is symmetrical: two identical major thirds stacked on top of each other. That symmetry means the chord has no clear sense of up or down, giving it a floating, slightly dizzying quality composers reach for when a moment needs to feel suspended or unresolved.
Other chord types
MajorMinorDiminishedSuspended 2ndSuspended 4thDominant 7thMajor 7thMinor 7thMajor 6thMinor 6thMinor Major 7thDiminished 7thHalf-Diminished 7thAugmented 7thAdd9Dominant 9thMajor 9thMinor 9th6/9Dominant 11thMinor 11thDominant 13thMajor 13thMinor 13th7sus47b57b97#9Dominant 7#11Minor 6/99sus4Power Chord (5)Minor Add9Add117sus213sus4Minor Major 9thMajor 7#11Major 9#117b1313b913#117altAugmented Major 7thMinor 9b5Quartal (So What)