I'm interested in the appearances of elements of H.P. Lovecraft's Cthulhu Mythos in D&D previous to the publication of Call of Cthulhu in 1981. Is there a comprehensive, detailed list available for those appearances?
There's a post on the Zenopus Archives titled The Cthulhu Mythos in D&D in the 1970s which presents a very detailed and reliable-looking "chronology of early references to the Cthulhu Mythos in Dungeons & Dragons".
For additional details and more, intriguing entries of the Mythos' unspeakable D&D history, do read the article on Zenopus Archives.
Disclaimer: I'm in no way affiliated with Zenopus Archives. Am just rather thankful to them for their work on this topic. :)
All you need from Gorgonmilk & TSR: http://gorgonmilk.blogspot.com/2013/05/ia-free-lovecraftian-supplement-ocrd.html