The Portable Freeware Collection Forums

Playnite is a MIT licensed FLOSS client for popular online game services such as Steam, Origin, GOG, Battle.net and Uplay; it looks cool and has a portable version, but I'm not a gamer (apart from a couple of really old games like OpenTTD), so can't really judge its worth... required DotNET is v4.6.

Playnite is open source video game library manager with one simple goal: provide unified interface for all your games.

Playnite latest release (currently v4.3.0) can be downloaded from https://github.com/JosefNemec/Playnite/releases.