What jobs were open to women in the Regency period?

There were only a few occupations that women could hold that would still be deemed respectable. Anything to do with the shop was not. However, a woman with good breeding fallen on hard times could be a governess. Her charges were usually girls, however, she could also watch the younger boys of the family. It was a lonely position with no servants being your equal so they would not talk with you. You would have to take your meals alone or with the children. The family sadly ignored their governesses most of the time.

A companion was another job a woman could hold. But again it was not ideal. If you were a younger lady you might become a companion to an older relative. You would be at their beck and call. 

Sometimes a younger widow would require a companion. That position might prove slightly better as you would be able to go places, but you would also live in the shadows. No matter which type of companion type situation that you would be able to hold, you would be considered a dependent and anyone without money was looked down on.