Consulting

This is a loose term. It could be almost the same as partially employed. There are no benefits no insurance, in other words one is alone. It is expected that the clients pay extra so there is enough to pay for medical expenses.

A client base is necessary to have a steady income. Most of all the services have to be appreciated. The client has to make money, otherwise one doesn't get paid.

Just for completeness I will consider here any intellectual work that does not get paid immediately. For instance if I write a book, and then I try to sell it, that could be filed in this category.