Fallout 3 secret weapons

Answer 1

There's plenty of special weapons. You have the rare weapons like plasma rifles and pistols which can only be found when you encounter enclave soidiers. The laser gatling gun which is hard to find unless you get it as your leaving the Enclave base or you can a get an improved version called vengence in the deathclaw sanctuary not far from their base. There's a alien blaster, use YouTube to give a better description how to find it. You can find Lincoln reapeater in top floors or Lincoln museum. The fatboy can be found in the Germantown police station and the experimental mirv (a fatboy that shoot 4 nukes) is in the Nat Guard armory if you can get to it. There are certain people or places in the game what have some powerful versions of the regular weapons in the game. The terrible shotgun, ol' painless or the Xuanlong Rifle are few of the improved versions of more common guns as well as melee weapons too. That doesn't exclude the weapons you can make upon finding the schematics. The bottle mine, rail gun, rock-it launcher, dart gun, shishkabob and the nuka grenade are the available weapons you can make upon finding said schematics.

Answer 2

If you mean unique weapons here are some:

A3-21's plasma rifle. - upgraded version of the plasma rifle

Fat man- Experimental MRIV is the upgraded unique version

Alien blaster- Firelance is the upgraded version

Fawks super sledge - upgraded version of the super sledge

Smugglers end - Upgraded lazer pistol

Wazer wifle - upgraded lazer rifle

Lincolns repeater rifle - Upgraded hunting rifle

Xaulong assult rifle - upgraded assult rifle

All these are unique varients of the normal versions that do more damage, are worth more and are just overall better.