A good place to look for configs not listed on their download pages, is this:
http://www.hovercontrol.com/cgi-bin/ib3/ikonboard.cgi?act=SF&f=53 .
That's the Hovercontrol forum dedicated to HTR. There are a couple threads stickied at the top specifically for the development of config files, which include some configs. Also, read through the forum. Some people post config files they've made for specific aircraft.
The forum includes a search feature, as well. Sometimes you can plug in the aircraft you want, and see if the search turns up a config file for it. Often, people post the configs just as a text entry to a thread. You have to copy it over to a new, empty, .txt type file, and rename it with a .cfg file extension. It's a good idea to keep the .txt file so that you can make changes of your own, save them, and then make a new .cfg file out of it for your own use.
Finally, all else having failed, make your own! You'll need some information about the aircraft to do so. Various and sundry size measurements, weights, power available, rotor speeds, and so on. Take an existent .cfg that is for a similar aircraft, if you can find one, and make a new .cfg file with your plane's settings. The program comes with excellent documentation on how-to make a .cfg file from scratch, and also, documentation what each and every entry to the .cfg file does to the helicopter.
Remember, every system is different and unique. What's perfect on your system is crud on your best friend's. It's a good idea to learn the .cfg file entries, what they do, how to adjust them, and so on.
Something else to consider: Jordan Moore, an amazingly well educated and knowledgeable helicopter developer, discovered a number of settings in both the aircraft.cfg file, and the .air files of a helicopter that are erroneous, even from many other devs, and certainly from MSFS, and what to do to fix these errors MSFS contains. Even if you don't choose to utilize HTR, which you really, really, should, these changes Mr. Moore recommends are equally important, and should be entered.
Part 1 may be found here:
http://www.hovercontrol.com/artman/publish/article_67.shtml , and part 2 here:
http://www.hovercontrol.com/artman/publish/article_88.shtml .
Finally, I don't recall that Fred Naar's (the author of HTR) latest version for FSX is in the HTR forums. Version 6.2, unless he's updated it again. v6.2, I believe is for FSX:SE specifically. V6.1 is for FSX and P3D. I believe. You may have to do a Google search for the specific version you want. But they're out there, readily available.
Good luck, and have fun!
Pat☺