If you are interested in ASL, I think a good resource is: https://www.lifeprint.com/
Also, I understand that it's hard to compare, because most people don't speak any sign languages, but is there something similar with sign languages?
Honestly, I feel weird desire to learn some sign language, but there's absolutely zero practical reasons for me to do so, and I wonder if learning, say, ASL, could help me interact with deaf people in my country or somewhere else. Sure, I won't understand them when they speak their local dialect, but is there something common that most deaf people would probably understand?
Most deaf people that know separate sign systems or sign languages will figure out ways to communicate across those language barriers at extreme speed. They are unmatchable charade experts.
I have seen deaf people from different continents have entire conversations in pidgin they bridge together over a few minutes.
ASL is perhaps more universal than English in one way. Most missionaries that established ASL Brought it with them as their primary teaching tool to deaf children.
So from Jamaica to Ghanna, Canada, many places in Africa, there will be many locations that sign a local variant of ASL. Perhaps maintaining 50-60% of the parent sign language.
ASL’s parent sign language is French, it is one of the older sign language and so has maintained less of its French roots, but we still use French twos and threes in our signed numbering system.