Printable Worksheets and Flashcards for fun learning.
Discovery FlashCards - Discovery FlashCards is a unique free program that can help you study.
Anki - Anki is a program which makes remembering things easy. Because it's a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
Printables - Free printable templates for your mobile sketching
Memcode - Flashcards: for coders and scientists. Open-source, free for all.
Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
Logseq - Logseq is a local-first, non-linear, outliner notebook for organizing and sharing your personal knowledge base.