iTypeWriter cydia tweak provides the most realistic type writer sound effects available in Cydia.
Turn your device into a classis type writer with iTypeWriter.
Backspace, Return (Ding!), Space, and every key press dynamically changing. No word will sound the same. iTypeWriter also gives the ability to add Haptic Feedback (Device Vibration). This is NOT a WinterBoard theme, but a Mobile Substrate tweak.