iSight insight.

Fascinating. The original Firewire 400-connected Apple iSight (VGA) webcam works after a fashion in macOS 10.15.6, with the right adaptors, that is. The microphone part is no longer operative but the camera does work, but in Zoom it's best without virtual backgrounds active.

The connectors I used are the Thunderbolt 3-to-Thunderbolt 2 adaptor, the Thunderbolt 1-Firewire 800 adaptor & a Firewire cable with the 9-pole 800 connector at one end & the 6-pole 400 connector at the other.

Being only a VGA camera, the quality isn't great but it is usable.