I just found this app through somebody in
/r/bodyweightfitness. It's called MadBarz (
https://madbarz.com/).
This image is the reason it interested me. Without having checked it out, it looks and sounds like a free app that gives you a bunch of free exercises and exercise plans. You can customize it depending on what you have for equipment (including 'none' like that picture).
I like these types of apps because I frequently want to exercise for 'just a few minutes'. I often don't want to go to the gym or to the park to exercise.