`jq` is pretty much the only one solving a real problem that no existing tool solves IMHO. Most of the others are rewrites for some opinionated 'better' (faster, syntax highlighting, written in Rust or whatever...).
As stated elsewhere linqpad is really great for testing ad-hoc, throwaway C# code (much more than just linq expressions). It kind of like a REPL for .net.
Me too. I also hit the back button since I didn't want to watch a video. Would have been good enough with a link to some textual explanation and images.