Diminished Chords

We’ve got diminished chords and what I believe is the m7b5 (slash thru a circle). Am I overlooking diminished 7th’s? Thanks!

Diminished chords in Strum Machine are played as dim7 chords (1-b3-b5-bb7 or 1-b3-b5-6) as opposed to a diminished triad only. And you are correct that the ø represents a half-diminished or m7b5 chord (1-b3-b5-b7).