VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
Vanilla Music - Vanilla Music is a clean, simple and opensource music player for Android.
MX Player - Powerful video player with advanced hardware acceleration and subtitle support.
AIMP - AIMP : Free Audio Player : Официальный сайт программы
VPlayer - VPlayer - a free music player for VKontakte.
MoboPlayer - MoboPlayer is a video player for Android that plays most video formats.