The Mean Greens - Plastic Warfare!

Team Fortress 2 (TF2) is the sequel to the game that put class-based, multiplayer team warfare on the map. One of the most popular online action games of all time, TF2 delivers constant free updates including new game modes, maps, equipment and, most importantly, hats.

Cube 2: Sauerbraten is a free multiplayer/singleplayer first person shooter, built as a major redesign of the Cube FPS.

Garry’s Mod is a sandbox game only available on Steam.

OpenArena is a community-produced deathmatch FPS based on GPL idTech3 technology. There are many game types supported including Free For All, Capture The Flag, Domination, Overload, Harvester, and more. There are 17 unique player models to choose from and 12 weapons.

Freedoom is a free first-person shooter under continuous development. The Freedoom project aims to create a complete free content game based on the Doom engine. Combined with the engine, Freedoom is also compatible with game modifications made for the original Doom games, made by Doom fans and artists over the decades.

16+Blip & Blop: Balls of Steel. What do the Smurfs, Super Mario Bros, Lara Croft and the Care Bears all have in common? They're all baddies in Blip & Blop! Although it is hard to believe, apparently these cute little friends are all actually pretty bad guys - and it's up to you to take care of them! Don't tell Papa Smurf you played this! (c) Loaded Studio. From 2002. For Microsoft Windows.

World of Padman is a incredibly meticulously designed and multicolored freeware fun-shooter for young and young-feeling people. You make your way through lilliput maps equiped with plastic guns.With 5 game types, 11 player models (even with diverent skins) and over 20 maps in different variations, WoP 1.5 is appareled with a ton of features and thus one of the biggest freeware shooters.