Just a few recommendations:
TONG DAM OR BLACK GOLD: One of the best tasting Thai mango tried in Thailand. I don't know if anyone grows it here in USA or taste tested it. High Brix, doesn't have floral/honey characteristics like NDM.
OKRONG OR OKRONG TONG: One of the sweetest of Thai mangos with some complex after taste, few strings near the seed. The cons are its small size and very few strings; nonetheless, would have been a very good cultivar.
PIM SEN MUN: Clean, sweet mango having less floral scent.
BKM : Very sweet, gorgeous deep orange flesh. Little hint of mango flavor with lacking in acidity.
MAHA CHINOK: Gorgeous color and exceptional shape similar to Shwehintha from Burma. lot of people confuse this mango with Banana mango from Thailand. It is way better than NDM. But it is overrated though.