In this category, I have discovered that a bit of imagination and improvisation can help. Over the years there has been a vast array of accessories available. However, in keeping with my theme, I have tried wherever possible (and practical) to obtain vintage items from the same era as the camera.
If you intend to use the equipment, some of the vintage accessories are still a good match for the capabilities of the cameras (eg lightmeters, rangefinders etc). However, in other cases, I have found that more recent items (eg tripods) are simply more functional and practical, and there is less risk of damage to the vintage cameras. Later model flash units are almost certainly the go for practical purposes, however period units definitely look the part for display.