Pogo is probably the simplest music player you can find on Linux. It has two panes: on the left is the filesystem view where you can pick files to add and on the right is the playlist where the added files appear. That is it! The player is so simple that is no shuffle or repeat mode.
To install Pogo use its PPA:
$ sudo add-apt-repository ppa:pogo-dev/stable $ sudo apt-get update $ sudo apt install pogo
Tried with: Pogo 0.8.3 and Ubuntu 14.04