hedwards: The game is really for a certain kind of player. It's better to think of Postal II as being a sandbox game before anybody really knew what a sandbox game was. There's something rather satisfying about gunning down an entire marching bad when I'm having a bad day.
As far as being forgettable, isn't that like virtually all games of the era? How many of them do people really remember that aren't by iD or 3d Realms? You'll probably run out of titles rather quickly as the bulk of the remainder are Unreal.
clarry: I mean if we're talking late 90s to early 2000s, that includes titles like System Shock 1-2, Deus Ex, Rainbow Six, Ghost Recon, Operation Flashpoint, Soldier of Fortune 1-2, Strife, MOHAA, RTCW, Vietcong, Half-Life, NOLF, Counter-Strike... pretty memorable, I'd say. And I think Postal 2 is quite memorable too; as far as I'm concerned, there's nothing wrong with being memorable for eggy humour and generally a different (sandboxy) approach to gameplay.
That's still an extremely short list of games, several of which I'd never even heard about until recently and several more that I haven't thought of in years.
But, even granting all of those, it's still a pretty short list of games for the time period.