UPDATE: Mike Bartus discovered an error in the files — I am so embarrassed! The 0% cyan and 5% cyan pages were incorrect. Thanks for the heads-up, Mike! I’ve fixed the error and posted new files. A reminder: they’re just C+M+Y (no black) because all of the CMYK permutations would result in way too many pages. But I hope you still find the files useful.
Remember when printing companies used to give out free tint sample books, showing combinations of cyan, magenta, and yellow so you could get an idea of what your CMYK combos might look? I haven’t seen one in a while, so I have created files so you can print your own. Of course, unless your printing device is carefully profiled, your output won’t necessarily match a commercial printer’s results. But if you print in-house, you may find them helpful. They show only combinations of C+M+Y —adding all the black combinations would result in over 400 pages, so I’m afraid you’ll have to imagine what adding, say, 15%K might produce.
I’ve provided two versions (same links; new files):
Hope you find them useful!