MFPlayer HD

Best media player for iOS that plays music by folders! Now with Apple CarPlay support.
No more sync process with iTunes, just put your music into Documents of this application and you are good to go!

How to prepare folder:
Create folder for each album you have. Additionally you can create folder with the name of artist and then put folders with albums inside it. If you have album art put it inside each folder and name it as "folder.jpg". You can also search for album atr on the web from inside this application just tap and hold on any folder.

How to upload files:

Connect to Mac or PC
Run iTunes, switch to Apps and scroll down to Documents. 
Find MFPlayerHD and click on it. Drag and drop folders with music files to the right side.