Snowball Smart Notifications - Get the notifications you want and none of the rest

EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.

Push More - Receive webhook requests in Telegram

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

Pusher Beams - Send push notifications programmatically at scale

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.