Institutional Repositories (IR) is for content published in paid-for journals and then self-archived as discipline repositories

• Africarxiv  – preprint service for African scientist.
• Arxiv physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics.
• BioRxiv – for biology.
• Engineering archive 
• PhilSci  – an electronic archive specifically tailored to and run by philosophers of science, including general philosophy of science, philosophy of particular sciences (physics, biology, chemistry, psychology, etc.), feminist philosophy of science, socially relevant philosophy of science, history and philosophy of science and history of the philosophy of science.
• PsyArXiv – for Psychological sciences.
• PubMed –  for biomedical and life sciences.