Right off the top of my head:
The Redeemer (Unreal Tournament). Why? It fired nukes
The Gravity Gun (Half Life 2). For obvious reasons
The “BFG” (Half Life: Opposing force): No not the one from Doom or Quake. This was a BFG featured in Half Life (That’s right. Half Life had a BFG) . The difference about the one in Half Life is that as a secondary fire it could teleport you to an alien dimension where you could explore for a bit before returning you back to earth in a different location.
The Shrink Ray (Duke Nukem 3D). What other game let you literally crush your enemies by reducing them to the size of a roach…then stomping on them? So much damn fun
Golden PP7 (Goldeneye64). I played Goldeneye exclusively just to use this gun. One shot killed which may sound boring until you remember that in Goldeneye everything explodes. Firing the Gold PP7 around like crazy resulted in tons of explosive fun. Ah those were the days
The Fusion cannon (Descent). In Descent there was a glitch where if multiple enemies stacked together, the fusion cannon would blow them up entirely in one single shot. Plus the fusion cannon looked and sounded awesome. SHOOOP PEOW! BOOOOM!
The Minigun (AVP2). AVP2 had the coolest minigun. It looked badass, it sounded badass, it handled badass, it did a badass amount of damage. The one in TF2 is a kids toy by comparison. The AVP2 minigun was for men. It struck fear into the hears of Humans and Aliens alike once they heard its loud whirring motors, let alone its meaty testicular fire sound. Anyone caught in the way of this thing died in milliseconds. Too bad I never saw it again in the sequels.
I might think of other later, I played many games and liked many weapons