For a period of time I worked for a patent company. If I had a dime for every useless brainfart that came across my desk Buckminster Fuller would have been right.
Here's a very large percentage of what people come up with when they think of something-
Mechanized toilet seats of some type
A generator connected to another generator so that one runs the other and you get free electricity.
A fishing lure that really works.
A remote locator (no not the GPS version for finding people in an avalanche, a beeper on your TV remote so you can clap your hands and find it in the same place every time).
The funny part about the last one is that it was explicitly stated on the disclosure form that those are not acceptable. The really funny part is that as stupid as that is, it replaced the idea they had before filling out that form.
A new button on their phone that does something else. Yes, a button. No electronic functions or circuitry behind it, just a button that you push which magically does what you think it should.
And occasionally someone who wants to put an electrode in each pole of the earth and use it as a battery.