So. At this point, I’ve seen a handful of characters *and actors* who are, afaik, men, who use ฉัน instead of ผม.
There is no apparent common thread between them, aside from “vaguely goth” for the characters. (And that’s more of a joke that has to do with the shows I watched recently.)
Anyway, this is pointing to more nuance and complexity wrt first person pronouns than: “ฉัน is for women and ผม is for men”— which is how the language apps like to claim they’re used.
Updates, because this is something I now tend to pay attention to:
Apparently Ajin from #EnigmaGMMTV also uses ฉัน. Thereby adding one more goth to the list. 
(Again, I do not actually think this is the criteria. I still maintain this is saying a lot about my choice of shows more than anything else lol)
But also, Missing Me has both Winny and Satang using ฉัน in the lyrics. And it’s also in the Thai title of the song: คิดถึงฉันใช่ป่ะ
Also adding Alan from Pit Babe to my list of fictional men who use ฉัน. Alan does not seem to be a goth. So my entire system is thrown off. 
(I kid. But the half-joke goth theory had a good run.)
Glitch