Anki

Anki is a program which makes remembering things easy. Because it is a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.

Anyone who needs to remember things in their daily life can benefit from Anki. Since it is content-agnostic and supports images, audio, videos and scientific markup (via LaTeX), the possibilities are endless. For example:

learning a language studying for medical and law exams memorizing people's names and faces brushing up on geography mastering long poems even practicing guitar chords!

Anki cards are displayed like webpages, so can optionally style them with HTML, CSS and Javascript.

There are big communities, e.g. r/Anki, and you can share and download decks among the community.

You can select from hundreds of add-ons developed by the community to extend Anki beyond its core functionality.