Fax machines and overhead projectors, if you live in Germany. Basically every office here still has a (frequently used) Fax machine and all schools still use overhead projectors.
It was actually quite a shock to me when my University retired their projectors in 2023. They sent an email to each and every student as a warning. Life‘s crazy here.
100% „der Projektor“. Bildwerfer makes sense as well, but I have never heard anyone use that word before.
It actually reminds me of the German version of me_irl (ich_iel) where they try to use German words exclusively even if it sounds completely silly.