I would think most Triangle real estate companies could help you list land in Morrisville. - it would just be a matter of which agent you interviewed and liked and felt would do the best job of getting it sold.
That said, if you have an unusual or bizarre (I mean this in a good way) property, there might be some agents who specialized more in those issues more than others. For instance, if it was zoned for commercial and not residential, that could require a more savvy agent. Or if it was unbuildable and wouldn't perc for septic, that might change who did the listing.
I know several agents who specialize in land and commercial deals, but they each have different niches. Feel free to contact me directly with specific information about your property and maybe I can give you a more specific answer. Kelsay@MyCarolinaHomeSearch.com If that's too odd for you, I encourage you to contact a few Realtors you know, give them specifics about your property, interview them personally, and ask them to present their marketing plan to you. Hopefully, you'll be able to weed out the good from the fair from the bad pretty quickly after seeing their presenations.
Good luck! Kelsay