ChordFrog

Try it before installing anything: chordfrog.app/chord-identifier plays a real piano chord and asks you to name it, and names what you play if a MIDI keyboard is connected. The iOS app goes deeper. Free Pond names chords live off any USB or Bluetooth keyboard, inversions and slash chords included. Four of the six modes need no hardware. Five levels, 24 chord types, sampled from a real Yamaha C5 rather than synth tones. Free, ad-supported. No subscription, no accounts, nothing locked.