One of my ideas 20 years ago was AdSense for cars. Random people get paid to put magnetic ads on their cars and earn based on how much and where they drive.

This was a good idea 20 years ago! There have been many of these since, including healthy revenues or minor acquisitions. You could have been part of it!

It existed for Laptops 20 years ago (or a little less). You got sent stickers to put on your Laptop and had to send weekly pictures with you Laptop and people in it, then you got paid.