I can see some claws coming out after I post this but hahaha oh well.
Today's standards are about being light skinned, model skinny and preferably mixed. That doesn't just apply to Thailand though because the same could be said for many other countries which is unfortunate. It's a reality that seriously needs to be challenged. Kim used to get a lot of shit about being fat. Now, I find Kim farrr from being attractive whether it's physically or mentally but it made me cringe whenever her co-stars or hosts would poke fun at her weight because she is not overweight by any means. Even when producers told her to loose a few pounds for a lakorn, it didn't make that much of a difference because she's naturally big boned. No matter how what she does, she's naturally going to look thick. Yes, she's a public figure and her image is part of her career so Kim has to work her way into meeting the norms of Thai beauty. As someone who doesn't even care for her, I could even feel the exhaustion of always trying to fit in, meet all these demands when she should be embracing her uniqueness. She's a good example of how ridiculous and overly obsessive the Thai's are about looks.
With that said, I don't care about Thai standards. Obviously most people would look plain without makeup which is why I think what is beneath all of that is what matters. My idea of beauty extends beyond physical appearances because if your personality is shit, then it will surface and show through your facial expressions and body language and... that ain't a pretty sight. Sometimes, there are people who aren't the most attractive looking but when they exude self-love, self-respect and confidence in themselves, it shows which makes that much more appealing. If they have some personality that differentiates them from others, that's a plus.
For example, I think Mai is probably one of the most striking looking half-caste actresses but her arrogance, hollier than thou attitude is a major turn off for me. She's the epitome of the whole Thai industry itself; the fakeness, hypocrisy, and egotism that majority of people have. Besides her pretty face, I honestly don't see any depth or substance which is why I only like her modelling work but could careless about her acting. On the other hand, someone like Yaya is gorgeous, not as defined as Mai IMHO but has the right personality, good work ethics and communication skills that makes her attractive. If I spotted both Mai and Yaya on the street, Mai is the one who would stop me in my tracks but Yaya is the one who would intrigue me to google her and find out more about her.
So to finally anwer your question as to who are the actresses that I think are most beautiful, I would say for mixed actresses I'd pick Yaya, Patricia and Sara. For non-mixed actresses, Now, Prang, Yoghourt and Fah are the prettiest of the bunch.