Handwrytten - Handwritten notes straight from your device. Huge selection of cards or design your own. Handwriting service integrates with 1000's of apps.
Future Me - Send an email to your future self
Handwriting.io - Real handwriting without the pen – no robots, all software
Incubate - Time-delay messaging app
Vuash - Send secret messages safely.
Felt for iPhone - Handwritten cards for the modern world