Some manufacturers (mainly German and British) made slightly smaller quarter plate versions of their 9x12 cameras, others just used a different focus/GG back and quarter plate holders that where a similar fit to their 9x12 holders.
The 9x12 fit roll film holder is usually 6x9 format on 120 or sometimes 620 film. The Rada ones took an adapter to give 6x6 as well, some of the Rollex must have done as well as I've some with two windows for the frame count which indicates more than one format.
As it happens I have quite a few Huttig ICA plate holders, Huttig became part of ICA who in turn became part of Zeiss Ikon and the ICA Huttig factory made the Maxinars.
9x12 film is easy to get as it's a modern standard, you'll need film inserts for the plate holders, I've just sold all my spares in the last couple of days. 5x4 film is too large, about the same length as 9x12 but wider, Quarter plate is about the same width as 9x12 but shorter which is why some 9x12 cameras were sold for Quarter palte as well.
If you want 9x12 holders that'll fit PM me, I can definitely help. I've 200+ metal plate holders of various sizes needing new homes, it's identifying what cameras they'll fit
Ian