Pixel Player is a customizable, lightweight, and powerful music player built for Android

Pixel Player is a customizable, lightweight, and powerful music player built for Android by kcrims from XDA Developers. In its list of features, you will find a Material Design inspired interface, customizable colors, gapless playback, lockscreen & notification controls. There are drag & sort queue management, 3 types of widgets, headset button controls, an equalizer (with DPS and Bass Boost support), artwork download, and tabbed interface.

But there's lots more, too. Stuff like long-pressing a song and having it play as the next one if shuffle is enabled, or the app closing itself if nothing has been playing for a while to save battery life.

Although Pixel Player is free, it also has a $0.99 paid Pro version that includes Folder Tabs, Hide Tabs, and some more functionality. Since Pixel is a fairly new app, it's being developed constantly and enthusiastically, so if you are into 3-rd party MP3 players, you might have just found a new favorite.