This is actually 18+ free and/or open source LMSs. Some are truly open source, some are freemium or other business models. If you want a list that goes well beyond Moodle and Canvas, this is a good place to start.
This is a summary of a project at the University of Toronto using Twine to create an educational game, plus an overview of Twine.
Although Twine is a tool for creating “games”, this project goes beyond games and gamification to think creatively about how the functions of Twine can be used to create activities that allow students to more directly engage with learning content in a hands-on experiential format that may not be possible in a traditional classroom learning space.