The World Bank is the single largest source of development knowledge. The World Bank Open Knowledge Repository (OKR) is the official open access repository for the World Bank's research outputs and knowledge products. 

OSF is a free, open platform to support your research and enable collaboration. 

OATD.org aims to be the best possible resource for finding open access graduate theses and dissertations published around the world. Metadata (information about the theses) come from over 1100 colleges, universities, and research institutions. OATD currently indexes 5,637,171 theses and dissertations. 

arXiv.org is an online distribution website and open-access repository with 1,866,054 academic publications in astronomy, mathematics, computer science, quantitative biology, quantitative finance, psychology, electrical engineering and systems science, and economics. The materials on this website have not been peer-reviewed by arXiv. 

IDEAS is the main bibliographic archive dedicated to Economics, and it is publicly available on the Internet. It indexes over 3,400,000 pieces of literature, including over 3,100,000 that can be accessed in full text, according to RePEc.