WordPress themes and plugins. They're all WordPress derivatives, therefore the code has to be GPL. Theoretically you can give away a copy of the code. In pract

WordPress themes and plugins. They're all WordPress derivatives, therefore the code has to be GPL. Theoretically you can give away a copy of the code. In practice, people don't. (Usually includd assets, i.e. images, are kept proprietary, and the thing is sold as an aggregation.) The thing they're really selling is security updates and maintenance.