You can sync your DriveThruRPG library either in whole or selectively to your Android device using this app. This also lets you access library items from our sister sites: DMs Guild, WargameVault, Storytellers Vault, DriveThruComics, DriveThruFiction, and more.

Note that this app is not optimized for phones. You can still use it on one, but it might be a little awkward.