I've been collecting posts on #facemask patterns. Here is a list of links you can check out. I will update as I see more.
***check with your local facility first. Each will have its own standard, so you will want to have your pattern and process pre-approved so you don't waste effort.***
https://www.providence.org/lp/100m-masks
http://checker-images.s3.amazonaws.com/…/MaskProductionInst…
https://freesewing.org/docs/patterns/fu/instructions
https://www.deaconess.com/How-to-make-a-Face-Mask
In the hoop: https://youtu.be/4it-9fb5BVA