Pitch layed out horizontally, the different scales vertically.
All basic chords on one line from the root note, going to the right.
Major chords starting on the rows with uppercase notes: major, maj7, 7/9/11/13 etc.
Minor chords starting on the rows with lowercase notes; minor, m7, m7/9/11/13 etc.
sus2 and sus4 variants above and below the third.
All the notes from a major scale conveniently together.
Enough room on an iPad screen for 3.5 octaves, with comfortably sized keys.
This sequence of chords can be played by moving one finger one key down-right repeatedly:
(The circle of fifths alternating with the relative minors.)
The same sequence, but instead the maj7 4-finger variants,
can be played by moving one finger down-left repeatedly.