When I was washing the Prius yesterday, I noticed the front licence plate bracket coming away from the bumper. In short, there was a minor "ding" a year or so ago, and the bumper was removed and repainted by Toyota. Whether the mechanic did it or it was a result of the "ding" one of the self-tapping screws used to put the bracket onto the bumper had stripped out and was barely holding it on the car. Ultimately, I solved the problem by finding a matching set of self-tapping screws that were a larger diameter to created bigger non-stripped holes in the bumper. Still, if this happened again, I'd not want to keep going larger. Is there a "plug" that can be inserted into a pre-drilled hole to create a refurbished anchor point for the bracket if it happens again. Ideally, if I moved some place that doesn't require a front license plate, they could be color matched to blend into the bumper to there aren't two holes in it.
You got me surfing; there's lots of DIY ideas, painting a plain fastener, and a prepainted, somewhat pricey option: BumperPlugs for Toyota
Just use a standard screw plug, the ones you insert into drywall etc. They expand enough to hold a license plate.
License plate bolt kits at every car parts store....some with backing bolts some without. Sounds like you need backing bolts.
I used bumperplugs.com to get some bumper attachments for a silver Porsche. (silver is hard to match.) Wonderful people to deal with, perfect match, still perfect after 6 years.
