A classic slap kiss : Game Rai Game Rak -they fall in love early, the slap kiss part comes after she loses her memory
Not slap kiss, just very good: Love Destiny- once she travels to the past it isn't very long before the ML begins to have feelings for the FL. The conflict between the two comes from the person who's body she takes over is a horrible person so he doesn't trust that she's actually changed.
Kao Waan Hai Noo Pen Sai Lub- the ML hires the FL to pretend to be his wife, there's a lot of push pull from the beginning with them.
Paen Rai Long Tai Wa Rak- It seems like he falls in love with her at first sight and again lots of back and forth with the leads
Ku Kaen San Ruk- ML falls for the FL early in the show. There isn't a ton of conflict between the two because she want's him to fall for her, but the FL is really feisty which is another trope in Thai drama
I'm not the biggest fan of the slap kiss genre of Thai dramas, so there are others that are considered classics like Sawan Biang or Jamloei Rak but I've never seen them so I don't know how good they are.