Mind

Courses & MOOCs

• Coursera — university courses and professional certificates (free audit on most).
• edX — courses from MIT, Harvard, and hundreds of partners.
• Khan Academy — K-12 through early college, practice and videos.
• MIT OpenCourseWare — free MIT course materials.
• OpenStax — peer-reviewed, free textbooks.
• Saylor Academy — free, self-paced courses (some ACE credit eligible).
• FutureLearn — short courses and online degrees.
• Alison — free courses with optional paid certificates.
• Class Central — meta-search across free and paid online courses.
• freeCodeCamp — full coding curriculum and certifications.
• The Odin Project — open-source web dev curriculum.
• Harvard CS50 — legendary intro computer science course, free.
• Stanford Online — free and paid courses from Stanford.
• Open Yale Courses — full recorded Yale lectures, free.
• OpenLearn — Open University’s free course library.
• Open Culture — curated free courses, audiobooks, and films.
• Udacity (free catalog) — smaller free library than it used to be, but still has solid intro tech content (most newer content is paid).

AI, Machine Learning & Data

• DeepLearning.AI — short courses and specialisations from Andrew Ng’s team (free to audit most).
• Hugging Face Learn — free, hands-on courses on LLMs, transformers, agents, and deep RL with certificates.
• fast.ai — Practical Deep Learning for Coders, free and still one of the best ML starting points.
• Google AI for Developers — Gemini, TensorFlow, and ML learning paths.
• Microsoft Learn — free role-based paths for Azure, AI, data, and dev.
• Kaggle Learn — fast, focused data science and ML micro-courses with notebooks.
• Anthropic Courses — free courses on prompting, building with Claude, and agent design.

Video Learning & Lectures

• TED — talks and TED-Ed lessons.
• CrashCourse — humanities, science, study skills.
• MinutePhysics — quick physics explainers.
• CGP Grey — maps, politics, concepts.
• 3Blue1Brown — visual math.
• Numberphile — numbers and puzzles.
• Veritasium — science and engineering.
• Kurzgesagt — animated big-idea explainers.
• TheNewBoston — programming tutorials.

Language Learning

• Duolingo — gamified fundamentals.
• Memrise — spaced-repetition vocab with native speaker video.
• Busuu — structured courses plus community feedback.
• italki / Verbling — 1-to-1 tutors with native speakers.
• Babbel — bite-size lessons.
• HelloTalk / Tandem — language exchange with natives.
• Clozemaster — vocab in context via sentence cloze drills.
• LingQ — read and listen with assisted transcripts.
• AnkiWeb — the king of spaced-repetition flashcards.
• Language Transfer — free audio courses with a thinking-method approach.
• Refold — immersion-based language learning methodology and community.

Books, Texts & Audiobooks

• Project Gutenberg — 75k+ public-domain ebooks.
• LibriVox — free public-domain audiobooks.
• Internet Archive — books, video, software, Wayback Machine.
• Open Library — borrow millions of ebooks.
• Standard Ebooks — beautifully formatted, carefully produced classics.
• Bartleby Lit Hub — the original free public-domain literature and reference archive (note: the rest of bartleby.com is now a paid homework service).

Programming & Computer Science

• Codecademy — interactive coding paths.
• MDN Web Docs — authoritative web docs and tutorials.
• web.dev — Google’s guide to modern web development.
• CSS-Tricks — deep practical front-end articles and guides.
• GitHub Skills — hands-on Git and GitHub courses.
• Exercism — free coding practice with human mentor feedback, 70+ languages.
• Roadmap.sh — community-built roadmaps for every dev role.
• Frontend Mentor — real-world front-end challenges with designs supplied.
• LeetCode / HackerRank / Codewars — coding practice and interview prep.
• CS50 — legendary intro CS covering C, Python, and web.

DIY & How-To

• Instructables — community projects and guides.
• wikiHow — illustrated how-tos.
• HowStuffWorks — how things work.
• Howcast — short how-to videos.
• Stack Exchange — expert Q&A communities across hundreds of topics.

Documentaries & Long-Form

• Kanopy — free with many library and university cards; high-quality library.
• Curiosity Stream — subscription documentary library.
• Top Documentary Films — curated free doc aggregator (ad-heavy).

General Knowledge, Quizzes & Research

• Wikipedia — still the web’s encyclopedia.
• Our World in Data — data-driven research and charts.
• Gapminder — global development data, tools, and teaching resources.
• Smithsonian Learning Lab — free resources from 21 Smithsonian museums.
• Google Arts & Culture — museum collections, virtual tours, and cultural stories.
• Mental Floss — trivia and explainers.
• Snopes — fact-checking.
• Sporcle — quizzes galore.
• Lizard Point — geography and more quizzes.
• FreeRice — learn and donate rice via the World Food Programme.

Math Tools & Problem Solving

• Wolfram|Alpha — computational answers.
• Project Euler — math and programming challenges.
• Desmos — graphing calculator and classroom activities.
• GeoGebra — interactive math apps.
• Brilliant — interactive math, science, and CS.
• Art of Problem Solving (AoPS) — advanced problem solving for strong students.
• Math Is Fun — approachable explanations and puzzles.

Science & Simulations

• PhET — interactive physics, chem, bio, and math sims.
• NASA — images, missions, curricula.
• Google Scholar — scholarly search.
• arXiv — open research preprints.
• DOAJ — directory of open-access journals.

Music Theory & Lessons

• JustinGuitar — free guitar curriculum, still the gold standard.
• MusicTheory.net — lessons, exercises, and tools.
• Ultimate Guitar — tabs and lessons.
• Teoria — theory and ear-training drills.
• Musicca — music theory practice.

Learn & Play Chess

• Lichess — free play, puzzles, studies, no paywall, ever.
• Chess.com Learn — interactive courses and lessons.

Words, Poetry, Etymology & Writing

• Online Etymology Dictionary — origins of words.
• Poetry Foundation — huge curated poetry library with poet profiles and essays.
• Genius — community-annotated lyrics and texts.
• Investopedia — finance explainers and dictionary.
• LessWrong — rationality and critical-thinking essays.

Note-Taking & Knowledge Management

• Zettelkasten.de — the definitive resource on the Zettelkasten method.
• Notion Academy — free lessons on building personal systems in Notion.
• Obsidian Help & Community — docs, plugins, and examples for the PKM power-user’s tool of choice.

Cooking & Kitchen Science

• Serious Eats — tested recipes and food science.
• Budget Bytes — tasty on a budget.
• Cooking for Engineers — technique-focused recipes.
• Reluctant Gourmet — fundamentals and methods.

Spotted a great site that should be here? Drop it in the comments and I’ll update the list.