Complete recorded lecture series in computer science, physics and mathematics, matched to the published course notes.

MIT OpenCourseWare - Full University Lectures

Densely researched animations on biology, space and the far future, each with a sourced companion document.

Kurzgesagt - Animated Science in a Nutshell

Thousands of freely licensed typefaces with weight previews, pairing suggestions and self hosting downloads.

Host for most of the open source world: source code, issue tracking, reviews and automated pipelines in one place.

Complete reference for SQL syntax, indexing, transactions, replication and performance tuning in the open source database.

A catalogue of millions of titles with editions, covers and borrowing links, built as an open editable database.

A community maintained database of artists, releases, labels and recordings, free to use and free to reuse.

Free preprint archive for physics, mathematics, computer science, quantitative biology and statistics, updated every weekday.

Lecture notes, problem sets and exams from thousands of real MIT courses, published openly with no registration.

The reference most developers actually keep open: language guide, full API listings, and runnable examples for every built in object.