Wisconsin! Smell our dairy air!!
New Mexico — but it’s a dry heat
“Nebraska~The Good Life” and it is.
Besides the ubiquitous Kansas Jayhawks and occasional K-State Wildcats, we also have the white oval with LFK, which stands for Lawrence Fucking Kansas.
There used to be a townie bar that opened at 7 am for the folks getting off of the overnight shift. “I Opened Johnny’s Tavern” was a frequently seen bumper sticker back in the 80’s. (Sometime in the 90’s - possibly after an ownership change - Johnny’s got taken over by the college crowd. I’m pretty sure it has been many years since they opened at 7 am.)
“We Don’t Much Care How You Did It In California”
That covers a large swath of the rural west.
And the “Highway 12” stickers. Got one on my rear window - we vacation on Hatteras every year.
You’ll see a whole lot of Florida Gators and Satchel’s Pizza bumper stickers in this town. I’ve lived in the area over twenty years and never been to Satchel’s. 
Another highway sign. People all over Michigan identify their 'hood with their “M-[Hwy No.]” stickers. I’ve got to get an M-99 one myself…
The most picturesque is M-22 that runs along Lake Michigan…
(What am I? Mapquest? Look it up yourself).
A friend moved to Madison, WI in the ‘80s, and quipped "I’m excited to live in the city with the most "Free Tibet’ bumper stickers per capita in the world."
This thread is reminding me of how little I get out on the road anymore.
Not representative of FL, but I see Tim’s Barbershop window stickers everywhere. There’s a Tim’s down the street from me and my then bf once got a haircut there. While he was in the chair, someone from the shop put a sticker on his car window. He was pissed! Anyway, that’s when I started seeing the stickers all the time and thought “Wow, they pull that obnoxious shit on everyone”. That’s when someone here told me Tim’s is a chain 
Lots of Tampa Bay Bucs stickers but oddly enough I don’t see too many Lightning or Rays ones.
One I saw here in the DC area several (10?) years ago was “NMCI Sucks!” Only in the DC area would someone have a bumper sticker complaining about the Navy-Marine Corps Intranet! https://en.wikipedia.org/wiki/Navy_Marine_Corps_Intranet?wprov=sfti1
I see a lot of bumper stickers from the Santa Cruz Mystery Spot, and I suspect they do the same thing. Some of these tourist traps post something along the lines of “By parking in our lot you give us permission to place a bumper sticker on your car.” When my family visited Tweetsie Railroad when I was a kid I remember afterwards my parents noticed some fine print on their receipt that said something like “If you don’t want a bumper sticker, leave your passenger side sun visor down”. Just by coincidence the passenger’s visor was down, so they didn’t get one.