Hello! :)

Need a new FPS to play! Preferably from the 90's to 05's or somewhere close.
DOS or Windows platforms doesn't matter much.

Blood
Quake 2
F.E.A.R

Tron 2.0- probably my favourite FPS ever. Great gameplay, varied weapons, unique world, superb art design and graphics (aged of course but still good), great level designs, and a good story that is also, against all odds, a proper and good sequel to the movie. A golden little miracle of a game. Unfortuantely not (yet?) on GOG.

Star Wars Jedi Knight- blasters, force powers, lighsabres and FMV cutscenes in all their cheesy fun glory. Unlike Jedi Knight II and Academy, this is still mostly a shooter, since the lighsabre combat is not nearly as good as it is in the sequels, and usually against non-sith enemies its best to stick to range weapons.

Outlaws- spaghetti western fun from Lucasarts with great music and animated cut-scenes.There is some annoying stuff, some puzzles typical for 90s FPS level design that really don't fit the setting and theme, but other than that it's really great fun provided you like westerns.

MoH: Allied Assault (+ Spearhead and Breakthrough)- a gamechanger when it first arrived, it still holds up as a good FPS, and the expansion packs are even better, with some of the best war-themed FPS action out there.

It might be helpful if you listed what you've already played.

You could probably just pick one and be pretty good getting a decent one.

Clive Barker's Undying
Redneck Rampage
Descent 1+2
Outlaws
Painkiller
AvP

Solid titles guys :)

Dark forces is great

Strife
SiN

F.E.A.R

is a really really good choice.

Unless you specify a bit more, its hard to say. There have been a ton of great fps games:
Fear
Boiling point
Far cry
Shadow warrior 2013
Return to castle wolfenstein
Mohaa
Call of duty 1,2 (before it went doooty)
Serious Sam

Just search Moby games or something.

I went with FEAR. I had it on disc AGES ago and loved it dearly.

I still have the original on disc :) Big box even.

Is it really have to be released that year?
I found this free. Haven't really give it a try, but looks old school and decent. Looks like it's released on 2009

Shock to the System.
and UT2004

Shogo.

There, I think that covers all FPSs sold on Gog.