Shooter
Shooter games are a sub-genre of action games, which often test the player's speed and reaction time. It includes many subgenres that have the commonality of focusing "on the actions of the avatar using some sort of weapon. Usually this weapon is a gun, or some other long-range weapon. Read the full article at the Wikipedia.
Quake II
by id Software
Quake II, is a first-person shooter computer game developed by Id Software and distributed by Activision.
Genre: Shooter, Action 
DOOM
by id Software
DOOM is a landmark 1993 first-person shooter video game by id Software.
Genre: Shooter, Action 
TO:Crossfire
by TNC-Clan
1.9.5.b
(15 Jan 2011)
Inspired by TacticalOps, a game based on Epic's awardwinning UnrealEngine, a group of friends took an ambitious step, creating a sequel...
Genre: Shooter, Total conversion, Action 
Inside a Star-filled Sky
by Jason Rohrer
Release 16
(22 Mar 2011)
An infinite, recursive, tactical shooter for one player by Jason Rohrer.
Genre: Arcade, Shooter, Action 
HeXen: Edge of Chaos
(11 Nov 2010)HeXen: Edge of Chaos will be a new and free game, based on the original Hexen game that was developed by id Software and Raven Software.
Genre: Shooter, Total conversion, Action 
The Dark Mod
2.04 (13 Jul 2016)The Dark Mod was once total conversion of Doom 3, and now is a STANDALONE GAME with the release of TDM 2.
Genre: Shooter, Stealth, Strategy 
FreeSpace Port
3.4 (15 Apr 2013)The FreeSpace Port is a user-made FreeSpace 2 port of the main Descent: FreeSpace campaign.
Genre: Shooter, Total conversion, Action 
Blue Planet
War in Heaven Act 3 (7 Jan 2013)Blue Planet is the overall name of a series of campaigns set 18 years after the events of FS2.
Genre: Shooter, Total conversion, Action 
Alien Swarm
1.34 (31 Jan 2010)Alien Swarm is an overhead view tactical squad-based shooter for Unreal Tournament 2004.
Genre: Shooter, Total conversion, Action 
Terminus
1.81 (20 Oct 2003)It had been thirty years since we first discovered the alien technology.
Genre: Construction and management, Shooter, Role-playing, Simulation, Action 
Unreal Tournament 2004
by Epic Games
3369
(13 Dec 2005)
Unreal Tournament 2004 is the next evolution of the first-person action game.
Genre: Shooter, Action 
Pioneer
20160710 (10 Jul 2016)Pioneer is a space adventure game set in our galaxy at the turn of the 31st century.
Genre: Shooter, Simulation