I assume that you are talking about the sort of cottage industries referred to in the link here -- ones that were the precursors to the factories that really brought in the Industrial Revolution. These cottage industries worked on the "putting out" system where families got raw materials from a richer person, made the raw materials into some finished goods, and then sold them back to the richer person.
Many goods could be produced in this way. However, the most usual things made in this way were textiles and clothing. It was relatively easy to give, for example, cotton to a family to make into thread and (perhaps) cloth. This sort of thing only required skills that people already had and so there was a large pool of people who could participate in this sort of production.