There's also Assault. From the less standard things, there is Trials (a platformer gametype), racing (a vehicle platformer gametype) and TAM and Freon that are some kind of Quack-ported gametypes that I never cared about, since they have lots of UTComp things going on in them.
As for DM, Ballistic Weapons seem to be popular, but they put me off with the looks. As for general mods you want to have, MapMixer might be helpful for admins, since it's an easy way to administer your server and keep it fresh with random mods and mutators. As for actual mods themselves, I will so some plugging and say that there are Unreal II weapons that I ported to UT2004.
