iPad: If you're the type to spread your files across multiple cloud storage services such as Dropbox, Google Drive and SkyDrive, then you probably have a bunch of apps loaded up on your iPad to access them. Documents by Readdle gives you access to all those in one place.
Documents by Readdle is a surprisingly robust app. Not only can you access all your cloud services, you can also access files from computers on a local network or via FTP. From there, you can transfer files across services, copy them to your iCloud drive, or just view them. You can also listen to MP3 files, watch videos, read and edit documents, and annotate PDF files directly from the app. If you're looking for an all-in-one file browser that has access to a variety of services, Documents by Readdle is worth considering.