SmartCards+ - Spaced Repetition Software for iOS. Modern, powerful and easy to use.
Harken - Flashcard app using smart repetition to improve your memory
FlipToMind - Space repetition app to help you remember everything
MemoStack - MemoStack is a flashcard software that help you memorize more things with less effort. It works great for test preparation, language learning, and more.
Zorbi - Spaced-Repetition Flashcards - Other tools are built by boomers, Zorbi is built by students.
Locked.app - Do you often forget if you've done something important?I keep coming back to check if I've locked the doors.You can check the toggle when you close the door or something.