Stellarium is an advanced stargazing app that provides a detailed celestial map and visibility planning features for optimal viewing times of celestial bodies. Fooview enhances multitasking with a customizable floating command interface, allowing quick gestures for various actions without interrupting current apps. Ampere displays charging metrics, helping users evaluate charger and device performance, and offers a cool-down feature for older battery packs. Each app has specific requirements, such as permissions for Fooview's overlays and approximate measurements for Ampere's data.