All of the modes of the major scale, melodic minor scale, and harmonic major and minor scales: 28 scales in total.
The notes have fields for scale name, scale degrees (e.g. 1 2 3 #4 5 6 7 for Lydian), parent scale and mode number, as well as the inverse scale (e.g. Locrian for the inverse of Lydian). Some of the scales have multiple valid names. I have used Rick Beato's naming conventions for these (e.g. Mixolydian #11 is the fourth mode of melodic minor).
There are five card types for 140 cards overall:
Front: scale name
Back: scale degrees
Front: scale degrees
Back: scale name
Front: scale name
Back: parent scale and mode number
Front: parent scale and mode number
Back: scale name
Front: scale name
Back: inverse scale