Formulation Challenge

I am looking for someone to help me to identify which is the best preservative options for a range of facial mists.

My brand is a natural and organic skincare line so I'd love to have a natural preservative however the most important element is that they are safe and shelf-stable.

I'm looking for somebody who can present to me all of my options in terms of preservatives both natural and synthetic, and list the recommended amount that they suggest also.

Looking to start this project ASAP also.