Free Fps games based on Doom and Wolf3d engine:
Project Crypt
Horror Fps similar to Cry of Fear
Project Crypt: The horror adventure about escaping a city overrun by monsters.
store.steampowered.com
DLC:
Project Crypt: The horror adventure built on GZDoom.
store.steampowered.com
Retroninjacyberassassin
Fps with gore and references to 90s culture.
This shareware floppy classic transports you to an alternate early 1990s, where the first person genre began not as a 3D adaptation of the side scrolling and top down shooters that came before, but rather as an adaptation of the 80s beat 'em up/hack n' slash classics.
store.steampowered.com
DLC:
Retroninjacyberassassin: Raider of the Lost Issue
A updated re-release of Retroninjacyberassassin: Raider of the Lost Issue, originally published by E1M1 Magazine.
store.steampowered.com
Fury's Sky
not Fps but is based on Doom engine, it looks more like Star Fox game:
Fly, fight, and survive in a flight action game like no other using the GZDoom engine!
store.steampowered.com
This one is based instead on Wolf3d engine:
GUN GODZ
Fps, you have to escape from jail of hotel
GUN GODZ is a first person shooter about gun, gangster rap and the rich culture of Venus. Players try to escape the jail of a hotel, which is the only building on Venus and is owned by a record-label owner who happens to be the God of Guns.
store.steampowered.com
If you are interested there are more games (free and not) I already posted in the past I found in this list
Are you looking for more games made on the Doom Engine? Then check this out......
steamcommunity.com