We've recently released Audiobit Music Player for Windows Phone 8.1 and it's getting great ratings from the users! Audiobit is a folder player that you can use to browse your phone and/or the SD card inserted into the phone and play the music files they contain directly from the app.
Audiobit does not use the MP3 tags or other information that the music files may contain. Instead, it uses the folder names and the file names of the music tracks to display the music on your phone. This way, you have the full control of how your music is organized and shown. You can connect the phone to your PC and use Windows Explorer (or better yet, our AB Commander) to move or rename the folders and the music files on your phone and the SD card it has. For example, you may want to move several folders containing albums from the same artist into a single artist folder, to keep them separate from other artists. If you don't like the way the tracks are displayed, just rename their files! And so on. Audiobit will show the folders and the tracks exactly as you have arranged them.
How to get Audiobit? From your Windows 8.1 phone, open Windows Store and search for Audiobit, then press the Install button after it's been displayed.