VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
PiP for Mac - Always on top window preview similar to the popular windows only OnTopReplica
foobar2000 - An advanced freeware audio player for the Windows platform.
Helium - Helium lets you accept payments by credit card for anything you want to sell online.
Winamp - Winamp is a media player that allows users to play multiple-file formats, arrange media in a varied file-management system, and play unique media with AAC encoding.
PiPifier - PiPifier is a macOS 10.