Following Unity licencing changes a few people started naming engine alternatives and here follows a list of game engines and frameworks to use in Game Development, most are free and open-source but a few are commercial. These were taken from suggestions on this thread (https://mastodon.gamedev.place/@djlink/111052944661218945), so it was a community collaboration, I just gathered them all in one place, thanks to everyone who contributed.
Feel free to make PR with more things