Here is a small selection of sources of grey literature specific to various disciplines.
This is not an exhaustive list. It may be worth viewing our Subject Guides to find other useful sources for your research.
The SSRN, formerly known as Social Science Research Network, is a repository for preprints and working papers devoted to the dissemination of scholarly research.
Disciplines covered are: Applied Sciences, Health Sciences, Humanities, Life Sciences, Physical Sciences and Social Sciences.