Before installing, try the free version "SuperLearning Brain Stimulatio".
https://play.google.com/store/apps/details?id=appinventor.ai_neuro098765.SuperLearning_stimulation

Use binaural, monaural and isochronic tones for stimulating the brain, improving your mental abilities and achieving lasting personal change.

Sessions:

- Concentration, FOCUS and Memory
- Creative FOCUS
- LEARNING - Complex Task - Frustration Reduction
- Performance Anxiety
- Anxiety Reduction
- Stress Relief
- ENERGIZER (Wake Up!)
- Your Own Session (Alpha for for Auto-Suggestion; Theta for Affirmations or Hypnosis; white, pink, brown Noise; Water, Birds, Brainsynchronization Background)