Cthulhu Mythos Worshippers
This is a tricky one. Deities and Demigods treats the various beings of the Mythos as monsters. Very few of them have specific class levels, which means that the method of using those levels to assign a probability that someone of that class worships a specific deity is a little questionable. However, the classes which are not represented are: Rangers, Paladins, Thieves, Monks, and Bards. Of these the only two that seem problematic are Monk and Thief; no one was expecting a Paladin to worship any of thise lot anyway!
Thieves can be rationalised, I think, in that they simply do not see anything very positive for themselves in the long-term goals of Cthulhu and Co. The end of all things is not very appealing to the person who loves shiney stuff.
Monks are harder. I personally absolutely can see Evil monk cultists but AD&D's decicision that monks must be Lawful rules out this most Chaotic of pantheons. One way around this might be Nyarlathotep masquerading as the head of some LE order who are unaware of the true nature of their "Master". Anyway, here's the table:
I thought I'd also throw in the pivoted table for Nyarlathotep showing the chance that a worshiper of that being is any given class, since he is the being most likely to be incountered in a non-combat situation: