Wolfenstein 3D
Although id Software did not develop another "Wolfenstein" game, as their development focus shifted to "Doom" shortly after release, and has never returned to the series, multiple "Wolfenstein" titles have been produced by other companies, sometimes using game engines developed by id. The first of these newer "Wolfenstein" games was "Return to Castle Wolfenstein" in 2001, a reboot of the series, and the latest is the 2017 "".
The Castles of Dr. Creep
A game enthusiast worked on a faithful game engine remake for the game since 2010 via reverse engineering, source code is on GitHub under the GPLv3. The remake got released on Steam by the original author and the remake author in September 2016. Available for PC (Windows, OS X, and Linux platform) it is sold for $2.99.