Minor 9b5 chords
A half diminished seventh with a ninth added. It softens the searching quality of m7b5 into something smoother and more modern, and it works well as the ii chord in a minor key ii-V-i when you want a fuller sound than the plain seventh.
Other chord types
MajorMinorDiminishedAugmentedSuspended 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 7thQuartal (So What)