Sway
Mindfulness and meditation techniques are a proven way to improve your mental wellbeing and ability to concentrate. Many of those require solitude. Sway was developed in collaboration with Danish mental wellness company PauseAble to let you practice "interactive meditation" in a variety of environments. Using a combination of soothing visuals, peaceful music, on-screen instructions, and audio cues, it encourages you to focus on slow, continuous body movements to help you focus and relax. There are multiple "levels" to work through, ensuring that the experience doesn't get stale as you progress, and since it's designed to work with headphones, you can use it anywhere you have enough room to move.