The 8 Best Free Moodle Plugins for Corporate Trainers - Capterra Blog
Customized reporting, integration with WebEx or Adobe Connect, gamification, Tin Can, and more.
Blog posts
The Top 8 Free/Open Source LMSs - Capterra Blog
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.