I'd say that certain cards do have sentimental/historical value, depending on the buyer. And, of course, they will only increase in value as they age and their rarity goes up.
A TNT2 is a landmark card because it was probably THE first 3d gaming card that could competently run the games of its time in 32-bit.
With that said, the TNT2 was a very mass-produced card, so it like other landmark cards like the 9700 Pro, 9800 Pro, GeForce 2 GTS, etc. are probably too common to have serious collector's value right now. Cards like the Voodoo 5 or even the FX 5800 Ultra would have nostalgia value for me because they were cards that were too expensive/slow/etc for their time but were novel for their day in several respects.
If I were starting a video card museum, I'd definitely want a TNT2 in there - but not an icky M64 version, if possible 😉 .