I’m actually surprised I could not find this integration,
But basicly a Lovelace card that allows me to set a reminder at a specific date/time and to specific targets or recipiants.
Could set it to use TTS for google speakrs like the home mini etc, or mobile notifiy. Better yet just allow you to call a service or setup different notification templates which can then be set to call specific services etc.
Then, at the date and time, that recipient get a notification of the reminder.
Pretty basic.
Nothing out there, if so I think someone should bite on this