As @oddiofyl mentioned - NOS are $$$. But once you experience them, it is painful to imagine life without them. And this is coming from a person who resisted tubes for couple of decades.
You can try the Gold Lions or Psvanes. In the "current production" lines, the Psvanes are couple of steps above the Gold Lions or anything else. I speak only for 12AU7s since I do not have experience with KT88 or 12AX7.