My all-time favorite lakorn OST that I always listen to in its entirety every time it plays on my shuffle list is...
"Lao Man Kaew" from the lakorn "Tae Bpang Korn" (Ann and Num's version). I wish I knew who the original singer was because his voice is too perfect with the instruments! Very angelic! Listen!
Then there's the original theme song of the lakorn "Roy Leh Sanae Rai" (Aom P. and Tik) called
"Sai Tah Yung Nun" by Sirasak. I never saw the lakorn itself but when I first heard the song, I fell in love with it!
I also like both of the songs from "Sawan Bieng" (Ann T. and Ken T. version):
"Jood Aon Kaung Chun Yoo Tee Hua Jai" by Aof Pongsak and
"Sin Sood Sak Tee" by Panadda.
"Kreung Neung Kaung Cheewit" by Amp Saowalak wasn't exactly an OST but it was the song that played at the end of "Samee Teetra" (Ploy-Pope-Jui version). I loved it the first time I heard it.
I also love all of the songs from lakorns, "Kaew Tah Pee" and "Oum Rak":
"Saeng Dao Kaung Hua Jai" by Narudom,
"Laew Jai" by Wichean,
"Kae Dai Pohb Ter" by Nop, AND
"Sarapahb" by Wichean,
"Gwa Ja Rak" Weerachai,
"Tee Haeng Nee" by Nop.
"Mai Rak Gaw Kae Bauk Gun" by Mon Supapon from the lakorn "Buang Rak" (Fang P. and Pepper version).
"Praw Mee Ter" by Num Sornram from the lakorn "Kau Morn Bai Nun Tee Ter Fun" (Nook and Num version).
"Hai Laew Gwaa Nee" by Parn Thanaporn from the lakorn "Dauk Som See Tong".
"Koo Gam" by Noona and Bie,
"Haam Jai" by Noona, and
"Kam Sunya" by Gun Napat from the lakorn "Koo Gam".
"
Dai Yin Hua Jai Dthua Aeng Riek Haa Ter" by Rome Pachata from the lakorn "Theppabut Sood Weha". In case you guys haven't heard it, see below: