"For Fit Girls Only"
Fit Girls Guide is an app that has videos and photos of various workouts that you can do to tone and trim yourself. There are also challenges to motivate you to keep it moving. With an active community and constantly updating content, you will keep this one for a while.
The workouts are effective and really push you. You can sort through to find the ones that you can do or like, and you can even make your own exercises. There are also graded workouts, though they start at a level for people who are already fit.
Just like the name suggests, the app tends to lean toward women who are already fit - there aren't "dumbed down" versions of the exercises. The videos also really eat away at your battery.