Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
CellSend - CellSend is a free service for sharing texts, links and pictures across all your devices.
Pushbullet - Pushbullet - Your devices working better together
Gotify - a simple self-hosted server for sending and receiving messages
Tresorit Send - Ultra-secure, end-to-end encrypted large file sharing.
AirMore - AirMore is a cross-platform toolset that can help you manage any Android device wirelessly.