Many/most type designers have built up a suite of test documents, but they tend to keep these to themselves. I don’t know of an online collection of these.

I’m sure they do. I’m not necessarily after any example pdfs per se — just some clues/insights.

Leslie Cabarga has a text sample he calls “Kern King,” for testing you-know-what, on his Logo, Font and Lettering Bible website, in case you’d like to check it out.

The problem with so many test documents available is that they don’t have dummy CE text in them! How am I supposed to test all of my Pro accents?

For testing all digraphs, rather than the majority of those that will appear in western languages, try the random all-digraph psuedotext. But I wouldn’t rely on it too heavily, because its letter distribution makes it look quite different from real text. Its main benefit is probably to find oddball kern problems such as ’qj’.

More immediately useful, I think, would be a text devoid of kern pairs, but still representing all letters and most high-frequency digraphs. That would let you focus on getting the side bearings right before diving in too deeply to tweaking the individual kern pairs - having lots of kerns to make up for poor basic fit is the classic mark of an amateur type release, and was certainly a problem in my first couple of tries in spacing my ATF Century Catalogue (see IKern vs Adobe InDesign's optical kerning and bouma of space craft for a more discussion from around that time).

cheers chaps