There presently are 70 eligible models. All have the requisite Hollow fuse and solid wing.
Admittedly, there has been some tweaking over the years. As mentioned, the TBF was (I believe) on one of the early eligible lists, but since it was a Del Gatto design, it was dropped. Also, the Bel Air was dropped, because it had a unique hollow airfoil. It was what I call a clamshell, in two pieces. I built one while it still was legal, and use it in Team Race. It would have an unfair advantage in Stunt, due to its fat foil section, when compared to the flat, solid ones.
Also, the Cessna 182 Tricycle was inadvertantly left off of the early lists (when you have so many models, something is bound to get overlooked). It is on the list now, and makes a nice model for Concours.
There is some debate within the NVCL to allow the P-38. It is not on the list as it stands, but if you showed up with one, I think they would allow it (in fact, I recall seeing one at an old meet). The Pro argument is that the canopy and center section is in 3-D. The Con is that the booms are profile, and profiles are not allowed. I say allow it.
If you really get into it, there are variations on certain models (like three different Little Bipe spans, two rather different Little Mustangs, etc) that are eligible in all forms. And the Blackhawk equivalents of course are eligible with slight differences vs the original Scientifics. Thank goodness these are available, because the old Scientific kits are scarce and unlikely to be built, and not everyone wants to scratch build.
Finally, I have argued that the 26" version of the Spirit of St Louis should be eligible (the 18" version already is). The bigger version is solid wing and Hollow Log. If you have a good Black Widow or Fox 049 and build lightly, it should fly OK. Currell