Thanks to all the talented people who provide CS fanciers with liveries, but I can't help but notice U.S. operators are underrepresented. Southwest--THE 737-300 airline- has the baby s*** brown and the blue-over-red but if there's a Continental (big operator) I've missed it. (New York Air / Continental was painted in striking red,too.) Piedmont had a nice classic livery. Western Pacific was known for it's logojet liveries. I understand the product--only just released in 1.0--might not have widespread traction yet, but there are some nice U.S. liveries waiting for an entry into ACE.

Same... we get plenty of operators that had 300s for a few years, but I haven't seen any of the newer Delta liveries, United, or SWA.

SWA had them flying until 2017! One of my first trips as crew at SWA was bombing around Texas in a -300 during the summer, thankfully those are long gone lol.

If you want them, request it here:
https://elmikey.wixsite.com/hangar226/livery-request

Just keep in mind that he only does real liveries. Don't ask him for the SWA Heart livery or any livery that has winglets. There are no winglets on the paintkit so he won't make any livery with them.
It's not CaptainSim making the liveries. If you want certain liveries find some place where you can request them. The link I gave you is one of the best you'll find, totally worth the $10.