Create your own course to memorize anything you want. Flashcard-based, with text formatting, with images, with multiple flashcard types.
Spaced-repetition app, focused on ease and speed of creating own courses, with flashcard formatting (LaTeX, image insertion) and cloze deletion flashcards.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.
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.
Brainscape - Find, create, and study SMART FLASHCARDS on any device. DOUBLE your learning speed using the most effective study system on the planet. Keep all your content in sync across Brainscape's website and your Android devices.
AnkiDroid - Memorize anything with AnkiDroid!
Kahoot! - Kahoot! makes it easy to create, play and share fun learning games in minutes—for any subject, in any language, on any device.
Anki Decks - Effortlessly Generate Anki Flashcards - From Any File or Text within Seconds. Simply Upload Your File -> Generate Flashcards -> Start Studying! Saves hours of manual flashcard creation and is perfect for medical students.