One cat I had woke one morning at what was obviously the very last moment. He was making for the litter tray, when he heard his sister was already in it, so he dashed into the bathroom and used the floor drain.
The cat I had when I was young and had a hard time getting up in time for work would stand just out of arm's reach and meow very loudly, if I turned off the alarm and didn't immediately get out of bed.
She got me to work on time on many early morning starts.
My parents couldn't afford an outside extension for the phone when they were newly married and a doctor's phone in those days had to be answered- If my mother was in the garden where she couldn't hear the phone when it rang, her cat would run down the garden to her, sit down and scratch his neck hard, so the bell on his collar rang, He had worked that out for himself.