JSTOR is one of the most well-known databases for academic articles throughout the world. While a significant portion of its content is behind a paywall, free access is an option for over 8.5 million journal articles, making JSTOR a helpful resource for all kinds of research.

LibGen provides free access to a wide range of journal articles, textbooks, and other forms of media that are mostly otherwise behind a paywall. The ability to download free textbooks is especially helpful to students at locations where resource access is lacking. To prevent downloading unwanted viruses, it is best to avoid torrenting; rather, download files directly from the site.

BBC Bitesize provides short-form and digestible science content for all levels. For advanced learners, articles are catered for the GCSE system, but the concepts discussed can be useful for high schoolers around the world.

The most popular global video platform, YouTube has long hosted a substantial community of learners and teachers. With nearly all video content is available free of charge, it is a go-to resource for a student’s questions on any topic.

RemNote is a note-taking application, available on mobile, as a web app, and on desktop, that allows users to create spaced-repetition flashcards within a hierarchic text structure. This functionality takes full advantage of the forgetting curve to optimize memory retention for notes that would otherwise exist in plain text. All of the essentials come with the free version of the app.

PTable is a gorgeous interactive periodic table that offers chemistry learners of all levels with quick and easy access to the properties, electron arrangements, isotopes, and compounds formed with all elements. Despite being funded with donations, PTable also comes with many unexpectedly useful features, including but not limited to dragging elements together to create compounds. It also offers a database of teacher resources to supplement its capabilities.

Yale Young Global Scholars is a selective two-week summer program hosted by Yale University. Attracting students from around the world, the program prides itself on inclusivity. Need-based financial aid of up to 100% tuition is available.

Fiveable is a global community of Advanced Placement students which offers virtual study groups and well-curated study guides and content for every single AP exam administered by the College Board. Also providing help for students with many different aspects of the US college admissions process, its services are completely free of charge.

Crash Course is a long-established online course database that extensively covers a wide range of subjects, from astronomy to philosophy to law, history, and science. Their videos are of very high quality, though it is important to note that their content is not specifically aligned with any major high school curriculum.

Khan Academy is an educational resource known throughout the world by teachers and students alike. When you’re confused on a topic, Sal Khan will (almost) always explain it better. With such brilliant quality, Khan Academy has branched out, covering subjects such as AP Economics and Psychology and many more, while still maintaining high standards for its K-12 math curriculum.

Paul Andersen’s videos on Bozeman Science are already widely used by science teachers across a variety of curriculums. Aligned largely to the Advanced Placement system, his videos are incredibly concise and well-produced.

Coursera’s online courses, largely administered by world-renowned universities and companies, cover all fields of study and allow for many flexible aspects in learning. Its courses vary from simple lecture series to full professional degrees. Though many courses require payment, a large number of high-quality classes are offered free of charge and some paid programs allow for free viewing of content (“auditing”), though without graded assignments.

Edx is a database of courses provided by universities, private companies and even international organizations. From skill-learning such as coding to academic learning such as topology, Edx provides courses for any and all interests. While certification is priced, most courses are available for free.