- Open Source Intelligence Techniques (Michael Bazzell) — Comprehensive OSINT book and toolkit
- Bellingcat OSINT Guides — Investigative journalism and OSINT techniques
- OSINT Techniques (Sector035’s Curated Lists) — Weekly curated OSINT links and guides
- Handbook of Collective Intelligence — Research and methodology (academic)
- OSINT Dojo — Free structured learning path for OSINT
- OSINT Curious — Blog, podcast, and tutorials (archived but valuable)
- Trace Labs OSINT VM & CTFs — Virtual machines and OSINT competitions
- Quiztime — Daily OSINT challenges on Twitter/X
- Bellingcat Workshops — Paid training on open source investigations
- SecJuice — Articles on OSINT, infosec, and cyber investigations
- NoHat — OSINT and cybersecurity research blog
- SANS OSINT Blog — Professional OSINT articles
- CyberWire Daily — Cybersecurity news and OSINT-adjacent podcast