Playnite is an Open Source manager and launcher for video games with support for Steam, Battle.net, Origin, GOG, and Uplay through a sleek, unified interface.
With Playnite, you can freely import games from Steam, Battle.net, Origin, GOG, and Uplay services, including games that are not yet installed. You have three options for viewing while using Playnite. You also have a custom game option - add any game or program with custom launch options, automatic update - so the app automatically updates to a new version and portable so you can take all your games with you. Additionally, there is an option to configure the database location for automatic syncing through Dropbox, Google Drive, etc.
Playnite is an easy enough to use option for gamers to manage their games.