Using the O-VF1 for The Q
There have been many different types of OVFs available over the years. I have a variant of the finder Waxwaine mentioned that is just marked "Made in Japan." The frame lines are fairly hard to see though, they may have faded over time. It is nice and tiny though.
I also have a Voightlander Kontour which is a very interesting two eyed finder but is a bit bigger on the Q.
One thing to keep in mind with any film era camera finder is that the frame lines are going to be wrong when used on the Q. They are marked for 3:2 aspect ratio while the Q (in full resolution) is 4:3. Not a big deal but worth mentioning.