Every company which is contributing to free software, in any form, is a free software business model. A business model does not necessarily need to be defined by its ethical stances; an industrial manufacturer might decide that for ethical reasons they will not use child labor, or use CFCs in their products. But simply saying “I will be ethical” will not lead to a business model¹. I.e. to start with free software and from there try to find a business model will only lead you to a few well-known examples; to wit:

https://www.gnu.org/philosophy/selling.html.en

https://www.gnu.org/philosophy/selling-exceptions.html

However, any business model which is otherwise ethical and supports free software in some capacity is a free software business model.

1. https://ozyandmillie.org/archives/comic/ozy-and-millie-96