SoftCards от Jan S.

This extension is in the alpha version and therefore neither bug free nor complete. 
It is intended to make creating flashcards as convenient as possible.
The current version is mainly intended for Android tablets with stylus.
Current features:

• Create and edit flashcards
• Create and edit categories
• Linking the cards into different categories
• Learning the flashcards using a simple spaced repetition system
• Exporting and importing cards