Even if we limit ourselves to the original France LSF and the English speaking world, there's American ASL, British BSL (sometimes called BANZSL because Australia and New Zealand use it), and Irish ISL too. That's like, four already. Anyway, most of the alphabets are one-handed, except the British which uses two hands, with the letter C being exceptional in that a single hand is sufficient.
Oatmeal Fucker !BYUc1TwJMU joined in and replied with this 1 year ago, 3 hours later[^][v]#1,326,752
Remember that time that two sign language signers got shot because a dude thought they were doing gang signs and they were ignoring him when he was throwing them back?