Thanks @Helpful Engineering for a lot of this stuff!

EasyEda is an easy way to share PCB layouts. It allows generating Geber and BOM files and ordering their manufacture in JLPCB.
https://easyeda.com/

Under normal conditions, the manufacture of PCBs at JLPCB takes 24-48 hours.
https://jlcpcb.com/

I have opened a public project called Ventilator Pandemic, where to share PCB.
https://easyeda.com/account/project?project=1b7620a497fb411595207ef79b21ed52

PCBs (in addition to electronics) can be used as mechanicals or structural component.
Examples
https://www.pinterest.es/cixelyn/pcb-as-structural