Disclaimer: All models presented here have been made by third parties and are not validated or tested for use in medical settings. Please refer to the linked sources for more information. I assume no responsibility or liability for damage to equipment or persons as a result of their use. This is not a scientific review but just a summary of the most useful DIY Models which appeared during the last weeks motivated by the shortage of supplies because of the corona virus. This document can be freely distributed as long as it is left unchanged and this disclaimer is included.