Late into the party and many have already been mentioned (The more it goes the more I use peco for everything).
I still have 3 more to add, that I use and rely heavily on a daily basis:
HTTPie: a CLI, cURL-like tool for humans
I still use curl regularly, but for most of my work I do use HTTPie a lot, it automatically escapes the inputs, makes them easier to add and edit, and the outputs are just gorgeous, much more easy to read
jq , a command line JSON processor, which make it easy to fitler, parse, transform, or just read json. The most basic use is the cat file.json | jq "." which will just treat the complete json. It does automatically beautify/indent it, colorize it. And when you're only interested in some specific json paths, or are searching for values, then the query syntax let you work with JSON directly from the command line. Go have a look at their short tutorial to get the idea of the potential, and you'll realize that's it's the ultimate JSON command line tool (cat is used for illustrative purpose, but with inputs from curl or httpie it becomes a great friend for working with JSON APIs)
Here's a quick intro to JQ: Handling JSON from the Command Line with Jq
jid, an interactive version of jq. I still use jq for any pipe-stuff or scripts, but jid is so nice for exploratory work in json data!
(On a side note, because I only spotted it very recently and didn't have the chance yet to use it extensively, http-prompt looks like a great tool build from HTTPie
