From Linux Gamer Guide - StrangeGamer.com
This page contains information about linux games and ports that have not yet been released.
You may also want to browse the "Upcoming" category for a list of upcoming games that already have their own page.
0 A.D. by Wildfire Games will have a linux port.
Bang Howdy by Three Rings Design is an MMO with a cowboy theme.
-  - An adventure game with an online multiplayer mode
DropTeam by TBG Software is a multiplayer tank simulation game.
Enemy Territory: Quake Wars
Enemy Territory: Quake Wars by Splash Damage and Activision
Mars, Land of No Mercy
Mars, Land of No Mercy is a turn-based strategy game set on Mars during the early stages of human colonization.
OpenAnno is an attempt to make a free Anno 1602/1503 clone.
Open Outcast: The Hidden Gate
Open Outcast: The Hidden Gate is a promising project that aims to create a 'real' sequel to Outcast. There have been some releases of artwork (see the links), but development is rather slow :(
Savage 2 by S2 Games is the sequel to Savage.
See Scourge: Dungeons
Stoked Rider by Bongfish Interactive Entertainment is a freestyle snowboarding sim.
-  - A tiny FPS taking place in a museum
BigFun Motorcycle Trials
Unreal Tournament 2007
Unreal Tournament 2007 by Epic Games is the latest sequel to Unreal Tournament.
Windstille is the current (2005-08-18) GotM at The Linux Game Tome.
It's a slow paced jump and run game.
Zymotic is the single-player counterpart to Nexuiz.
Ballistics by GRIN, is a 3D racing game where players pilot a hovercraft down a tube.
Second Life by Linden Lab is a Massively Multiplayer Online RPG (MMORPG) that gives players free reign to shape the in-game world as they see fit.
TA Spring is a 3D "Total Annihilation" engine.
Other Upcoming Software
FIFE previously known as Ianout - A free Fallout-like engine.