A number of databases uses the Business Source License (and its variants, usually including a non-compete clause). It acts as an option which vests (switches to

A number of databases uses the Business Source License (and its variants, usually including a non-compete clause). It acts as an option which vests (switches to a non-copyleft libre license) after n months. There is also the Polyform project but adoption has been low and their licenses are extremely controversial and unpopular.