The best app I have found in this category /free soft/. There is a desktop version and you can synchronize between mobile and desktop version. The only drawback is that the data can occupy significant amount of space and the app does not support storing data on external card. I use Samsung S5 which does not support adoption of external card space /Samsung states that this slows down the apps/ so I'm running frequently out of disk space.
September 16 2016