As I recall, there are three different widths for 6.5x9 cm sheet film, 2x3 (aka 2 1/4 x 3 1/4) sheet film, and 120 roll film. You're kind of in the same boat if you have a 2x3, 6.5x9, or 9x12 camera: buy whatever emulsion you can find, or buy X-ray film and cut it down under safelight, or make the setup and investment to recut panchro or color film in total darkness.
Same goes for postcard (3 1/2 x 5 1/4, IIRC) and 3x4 and quarter plate, half plate, and full plate, of course. You can probably get any Ilford emulsion available in sheet form from the annual "ULF bulk buy" event, however -- which isn't just ULF, it's custom cut for a lot of obsolete sheet film formats, plus uncut strips of 120 width, unperfed 35mm, etc. Buy-in is significant, but if well stored, the film will last a lot longer than the 2 year expiration usually given.