Apparently JMESPath is a better JSONPath/dot-notation alternative for querying JSON, while jq and jl are full-featured fully functional programming languages that happen to use JSON as their underlying data type.

I had never heard of jl before, but I've recently compiled an "awesome" collection of jq tools, libraries and use-cases at https://github.com/fiatjaf/awesome-jq that may be worth checking out.