Avis, with their preferred (free) program. When you get to the airport, open the app to see what car you are assigned and it offers options to swap to a different one - shows the pictures/colors/descriptions.
There is a preferred counter near the cars if you have any questions or issues.
We have with Alamo.
You just have to be sure the bar code is on the rental sheet you printed.
It always had before, but didn't in October and we had to wait a few minutes at the office by the cars before we could get our vehicle.