I'd reword it only slightly. Vendors listed on this page create Utilities/Scripts as add-on enhancements to the features and performance of Poser. I wouldn't use the word "programs" as Poser is the program, and utility/scripts are add-ons, not necessarily programs themselves.
Hmmm, maybe that's a bit off, as there's Wardrobe Wizard, which in newer versions of Poser, works within Poser, but I have the standalone version, which I purchased back when I was using Poser 5. I don't know how many folks who have it still use it. There's also CrossDresser which, I believe, works outside of Poser. Those could probably be called programs as they are standalone. OK, I just checked EvilInnocence's site, and they refer to CrossDresser as a utility, so I don't know how I'd classify it.
OK, just my 2¢, FWIW. I'll leave it up to you to decide which is more appropriate, as you're the one who has the list of vendors.