You pretty much got 'em all, sans perhaps a couple wildcats. Of the .50's, only two really make sense. The .500 linebaugh is smilar in performance to the .50 AE, but if you're opting for a revolver it may as well be the .500 mag. The .500 special is not explicitly chambered in anything, but is merely a practice round for the .500 mag, so it really can't be classified as a chambering. The .50 GI is as worthlesss as tits on a bull; less power and lower capacity than .45 ACP, and chambered in a $2,500 gun. Only the .50 AE and .500 S&W are easily available as factory rounds anyway.
Though it is chambered in the BFR, the .50 Beuwolf really isn't a handgun cartridge; The BFR is chambered in .444 marlin and .45-70 as well, which certainly aren't handgun cartridges.