[Ntfy.sh|https://ntfy.sh/] is such a basic idea, but has so much use cases. Just think about all the manual checking you need to conduct on your server. Maybe you need to SSH just to check the network status. Or maybe your server has a power outage, and you don't find out until you actually go to use it. These scenarios can be much less painful with a notification. Even better, imagine setting up a self-hosted notification server, where you can make a notification for anything you want. That's exactly what Ntfy.sh is made for.
Whether it's a direct linux binary, a Docker container, or even an ArmV6 cpu install, Ntfy.sh has install options for everything, and the setup couldn't get more simple. I opted for the Docker install on my Arch linux server.

Some of the cool use-cases of a notification service include custom progress checks on scripts or updates, or even server health pings. I have set up a simple ping for a game server I hosted, and it worked awesome.