Ib Sim Neej is the most common one that I know of...My uncle and his wife used it for their 10-year anniversary celebration vow-renewal. It's pretty good, though really old. =\
Dancing songs, as you might know, a common one is Som Sarn collaborated by Sek & Loso. I know there too used but if it's a Hmong event, I think they will be necessary. Lol.