Daily report + dynamic entity list (monitoring)

Hi!

After nearly a year on home assistant I am on a good path to a stable system.
For a more convenient way of monitoring the system, I now want to have a daily report (in slack) of entities with certain condition in a very dynamic way. For example all devices seen 24+ hours ago. Or devices with a low battery.
But I have absolutely no idea on how to implement this without template for every specific entity. I would appreciate any ideas on where/how to start.

Thanks and greetings!