Your SD card may not be fully indexed. Other is just a catch-all title for things not marked as specific type. I.E.: App, Music, Video, Pictures, etc.
Before deleting the Other on your SD card, you may want to find out what data is being stored there!!! Try using this App on your Windows 8 or higher PC:
https://www.windowsphone.com/en-US/h...pp-for-desktop I have found that by connecting to PC and running this App on Desktop it forces the phone to reexamine the contents of the SD card and your Other category might shrink while some extra goes into the appropriate folders by type...
Also see this Wiki... Even though it concentrates on internal storage there is some great material here.
How to free storage memory on Windows Phone - Wiki