Gotify - a simple self-hosted server for sending and receiving messages
Pushbullet - Pushbullet - Your devices working better together
Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
KDE Connect - Integrate Android with the KDE Desktop
Pusha - Send push notifications from your web or desktop application to your smartphone and always stay up to date with important events.
AirDroid - Access Android phone/tablet from computer remotely and securely. Manage SMS, files, photos and videos, WhatsApp, Line, WeChat and more on computer.