Put Jesus fish and Christian bumper stickers on your car. Put thin blue line flags on your car.
If you're in the south or rural areas put Trump stickers on your car. The cops will not pull you over for fishing or searching.
Hah. I was thinking the same way when I made my wife put her complimentary plastic "State U. Alumni" frame around the license plate when we bought a new (used) car together. We picked a clean, bland Japanese subcompact identical to thousands of other commuter-mobiles, partially for the economy but also for the anonymity.
The alumni frame basically proclaims to the world that you're a hopeless square, so I understood why she was embarrassed, but that was the whole point!
And even more than that, I thought it would imply that the driver was likely middle- to upper-middle-class (holding a 4-yr. degree from a selective university) and also likely grew up in this state (which is full of transplants). In other words: trying to wrap our illegality in the cloak of privilege, to hide it from the categorizing eyes of LEO.
We also put on the bumper-sticker of an AM radio station that isn't filled with right-wing talk shows but is definitely programmed to the tastes of conventional, older listeners.
She had another one on her previous car, a dented and cracked 20-y.o. beater with 200k miles on it, the kind of car that screams "Ask me for consent to search!" We spent a couple of years in it, parked for hours within every "high drug-traffic area" of the city, without ever getting pulled. So it kind of became a good-luck talisman.