Dominant 7th chords
A major triad with a minor seventh stacked on top, this is the workhorse chord of blues and functional harmony. Hiding between its third and seventh is a tritone, the same restless interval that gives the chord its itchy pull toward whichever chord sits a fifth below.
Other chord types
MajorMinorDiminishedAugmentedSuspended 2ndSuspended 4thMajor 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)