Big Buick signs were generally found in service garages & car dealerships.
The Buick nameplate & assorted logos were incorporated into the designs.
With dealers going out of business, some of their signage was sold to collectors.
Then there’s the aftermarket business that was created when vendors realized that there was a demand for larger than life units that Buick fans wanted for displaying in their garages.
Here’s a few I found in the past year that have been for sale on ebay.
(you can hover over the pics with your mouse for a description of the item)
Here’s some other items if you’re shopping for Buick merch:
(if you can’t see them, turn off your ad blocker!)