What is the most frugal new car out there ?

I just bought a new Honda Civic 2019 LX (most basic version) and it has a really great mpg, 33 city, 38 highway and there is also an "eco" mode if you want to save more gas (best used in traffic).

Now I'm a single guy that dates here and there so I know that a Fiat or a Smart Car would have a higher mpg, but it would not make me look very masculine and I have my limits, but in your opinion and research, what is the most frugal new car out there ? I'm pretty satisfied with my Honda Civic. I can drive 350 miles on a full tank and a tank of gas in my city is $30 ish (I live in Houston, which is a big oil city).