cottage industry

noun2

1. •
   A job or occupation carried out at home or on a part-time basis, historically often manufacturing work such as sewing, lacemaking, or spinning.

   • A craft such as quilting may be pursued as a hobby or as a cottage industry.
2. •
   A small-scale industry, with relatively few employees or a limited customer base or low economic impact.

   • Remote and difficult to access, many villages in China’s interior have developed a criminal cottage industry, involving anything from drugs to internet fraud to counterfeiting. — 2017