Charlie Banacos approach-tone exercises arpeggiated seventh chords (two octaves), approaching the root by a series of intervals, i.e.:

and then: 1 above + 1 below 1 below + 1 above 2 above 2 below 2 above + 1 below 1 below + 2 above 2 below + 1 above 1 above + 2 below 2 above + 2 below 2 below + 2 above then do this for each chord tone of that chord type (i.e. 1above for the 5th C E Ab G B C E Ab G B Ab G etc) and then for other chord types (e.g. 7, min7, min7(b5), dim7, aug7, maj7(#5), dim(maj7)) I generally put the metronome on 2+4 at 50bpm, and then start in one key at quarter notes, then move up a fourth as quarter note triplets, up a fourth as eighths etc, up til 16ths (effectively running the pattern through every key at different tempos):

etc. Generally, I've just been focusing on maj7, but a couple years ago when I got into this I made up a schedule to do different chord types on different days, because it takes forever just to get through one chord type.