LaunchBox - LaunchBox is a portable, box-art-based games database and launcher for DOSBox, emulators, arcade cabinets, and PC Games. Download it free!
Playnite - Source code generated using layoutit.com
HyperSpin - HyperSpin is an animated arcade frontend for Windows for use on Home Arcade Machines.
GameRoom - Make your video-games library shine!
GameEx - GameEx is considered to be the most powerful and feature rich front-end for MAME, GameBase, Daphne, PC Games and all command line based game emulators, along with being a complete Home Theatre PC solution.
Lutris - Lutris is an open source gaming platform for GNU/Linux.