Favorite #1 - S&W Hush-Puppy
The S&W Mk-22 Mod 0 Hush Puppy was devised for SF teams in Vietnam to silence guard dogs when on recon or S&D missions. It consisted of a S&W Model 39 modified with a slide-locking mechanism to prevent ejection of the empty round. A heavy sub-sonic load was used with the suppressor to minimize signature. Protective "ears" were added for the adjustable sights - a feature later made "standard" on the 439 model. Suppressor was highly effective. Operatives said the only sound was the hammer striking the firing pin for the first 8 rounds, then it started to get a little louder. After about 20 rounds, the suppressors sounded like a .22LR and were sent for rebuilding.
Favorite #2 - MBA Gyrojet Rocket Pistol
Designed from aluminum stampings, this gun was nothing more than a hand-held rocket launcher. It fired a 13mm solid slug filled with a rocket propellant, actuated by a primer on the base. Four angled exhaust ports imparted spin to the projectile and the smoothbore barrel allowed aiming (after a fashion). Quite fun to shoot, but not effective. At close range the round was barely moving 600 fps. It actually accelerated
outside the barrel. But by the time it's fuel was exhausted, the projectile weight dropped and it was no more effective at 100 yards than a .357 Magnum. Accuracy was also less than stellar.
Favorite #3 - High Standard Model 10
While it's not a handgun per se, it's a semi-auto 12-gauge bullpup that can be fired one handed. Used one of these in the 70's and liked it a lot. If HS had kept the model and refined it, it would have been a top-notch patrol shotgun.
As it was, the Secret Service bought over 500 of 'em with an eye towards VIP protection. One author writing about a CIA agent in South America armed him with a Colt .38 Super and the Model 10 shotgun with a shoulder sling for carrying under a rain parka. In one scene in the novel, he's faced with four agents of Castro coming after him. In an alley, they hide behind their 67 Chevrolet and he use three "steel cored" shotgun slugs to slice & dice the Chevy and the agents. The front sight is shown folded down. The shoulder piece rotates 360 to allow it to recoil against the upper arm just above the elbow when held one-handed. 4+1 Capacity. Mountable 2-D Cell aluminum flashlight (forward of carry handle) optional. All controls ambidextrous and right-hand ejection.