The Google Play store and Apple Apps store each offer millions of apps. Problem is unless you know what your specifically looking for its kinda hard to find apps of interest. Here are indexes for these stores that allows users to browse for apps using the index, enabling you to find apps that match with your personal interests.
virtual and augmented reality apps
science and social science apps
potpourri apps including antiques animals Beauty chat collecting comic books gardening literary making things Mystic Performing Arts photography
...........................................
play in Recreation apps
popular categories apps
business apps
travel and tourism apps
science and social science apps
graphic and language apps
wild and wonderful world apps