That's the 1st thing I did as well! In a word, none. No wood grips come on guns that fit the NV. But you can buy optional wood grips from Ruger's website that are made to fit your gun. Here's the two sets that will:
http://shopruger.com/New-Vaquero-Smooth ... nfo/19871/
http://shopruger.com/New-Vaquero-Rosewo ... nfo/19872/
Most will tell you to get custom fitted grips and you can even find them with factory Ruger medallions in many choices of wood.
But if you're the least bit handy, there's a simple, inexpensive option. I see you have a Vaq and Old Army which have the same size grip and it is very close to your New Vaq. If you pull one of those grips and lay it over your grip frame you'll see how easy it is to make them fit. The front edge is about 1/16" to long, sand that off. They will not lie flat over the lock because the NV grip frame is 1/16" narrower then the V and OA and the lock sticks out. Put the lock on a belt sander if you have one and sand or file 1/32" off of both sides of the lock, it will still work fine. Or if you have a benchgrinder just grind out a 1/32" hollow on the back of each wood grip. The locating pin hole does not line up. Drive out the locating roll pin in the grip frame. Tape one grip at a time firmly to the grip frame. With a drill bit the same size as the hole drill a new locating hole in the wood grip being careful not to go too deep and all the way thru!! Do the other grip the same and you're done.
The grip size you need to start with is Ruger's most common size and can be found used anywhere including on this forum. They came on the Old Army, original Vaq and New Model Blackhawks (except the newer Flat tops) and Super blackhawks with barrel lengths under 7 1/2".
You