Gamebryo is the licensable engine behind literally dozens of commercial games, including the last three Elder Scrolls titles, Bully, Catherine, Divinity 2, FallOut3, Civilizations 4 and Warhammer online.
That said, it does not have a proper entry because it’s status is currently unknown. The company behind Gamebryo went under, and all of their assets were purchased by a Korean company, Gamebase. It appears Gamebryo is still available for licensing, but their webpage went offline a few days ago ( As of August 7th, 2012 ) and I cannot firmly confirm Gamebyro is still available.
If anyone can confirm or deny either way, please do so!