Project Gutenberg
Free online library with over 60,000 books
Library Genesis
Free access to copyrighted books
Sci-Hub
Free access to paywalled and copyrighted scientific articles
Unpaywall
Free website that harvests paywalled articles
PW Megathread
Reddit megathread for piracy wiki
Surveillance Self-Defense
Guide on protection from online spying by the Electronic Frontier Foundation
Spyware Watchdog
Website classifying spyware programs and how to avoid them
DEF CON Archive
Info database for DEF CON, the hacker convention
OWASP
Open Web Application Security Project: nonprofit foundation working to improve software security