I wish there's more sad and beautiful love stories coming up from ch7... lately they've done a lot of action and supernatural lakorns -_- I'm fine with comedy but I still prefer sad love stories ^_^
Here's what I would recommand:
Rahut Rissaya (Noon/Paul) : this is one of my all time favourite lakorn so I highly recommand this
Sai luerd hang ruk (Aum P/Paul) : this one is surely the saddest... so much drama... it may be a bit confusing at first but it is actually really good ^_^
Sadtroo koo kwam (Yui/Ouan) : a heartwarming lakorn ^^
Duay raeng haeng ruk (Noon/Mos) : the storyline is good but I sometimes find it a little draggy.
Gol ruk game payabaht (Kob/Chakrit)
There's also So sanae ha with Aum P and Oil... My mom likes it a lot, as for me.... I don't exactly remember what was going on in this one because I saw it a long time ago XD I just know that I like it when I watched it...