Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
Handwrytten - Handwritten notes straight from your device. Huge selection of cards or design your own. Handwriting service integrates with 1000's of apps.
Pushbullet - Pushbullet - Your devices working better together
Mailjoy - Delightfully easy direct mail marketing. A DIY direct mail tool created for marketing and growth teams. Design, mail & track personalized direct mail postcards and letters. Digital marketers use Mailjoy to send data-driven mail campaigns.
Pushsafer - Send push notifications easy and safe to ios, iphone, ipad, android, windows, devices
The Simple Postcard - Text a photo to mail it as a postcard