I read something that said "Most of the cars with direct TPMS have a reset button located under the steering wheel" and the same was said about most Pontiac'*.
I looked all over my steering wheel and below it, and cannot find any buttons, just screw holes for trying to remove the steering wheel shroud or something.
Somewhere I read that once you reset it on the DIC you press the button under the steering wheel, but again I cannot find one on my 2006 Grand Prix GT anywhere.

I've never heard of this or seen it on any brand of anything. Not saying it is untrue, just I've never heard of this nor seen it. I've driven a lot of stuff over the last decade (thanks to business travel) and messed with lots of stuff (thanks to friends and colleagues with car issues), and I'm always pouring over these makes/models just to learn stuff about them, but never seen or heard of anything like this.

Same here, I have less experience, but never encountered one there either.

Bloomington Toyota says "

• With the vehicle off, turn the key to the “on” position, but don’t start the car. Hold the TPMS reset button until the tire pressure light blinks three times, then release it. Start the car and wait 20 minutes for the sensor to refresh. The tire pressure monitor reset button is usually located beneath the steering wheel. If you are unable to find it, refer to your vehicle’* owner’* manual."

A Honda site said "Recalibration should be performed when the inflation is corrected or changed. The procedure does not involve any tools, but is intiated by either a TPMS reset button below the steering wheel or by using a series of button presses in the i-Mid driver information center."

Maybe it is primarily Honda'* and Toyota'*, shrugs...

Yeah maybe so. Not a lot of them end up in the rental lots compared to, say, FCA, Ford, or Chevy products.