A reply asked for more details about what is and isn't "classic-era", but this reply appears to have been deleted while I was writing the following.
The last licensed NES game in North America was
Wario's Woods in 1994 (
source: Giant Bomb). The last in Europe was
The Lion King in 1995, and the last major unlicensed NES game in North America for several years was
Sunday Funday: The Ride, also in 1995. There was a huge gap from then to the next major western unlicensed release, that of
Battle Kid: Fortress of Peril in 2010. See the prominent date gap in
Wikipedia's list of verifiable releases of unlicensed games.
For several reasons, including the rise of NES emulation (iNES and NESticle) and the release of the Nintendo 64 (the same company's console two generations later), I tend to set the cutoff date for the classic era as December 31, 1996, though this is by no means official.