Eternal Terminal `et` when we worked from an office where our connection would drop regularly was a life saver. It's like Mosh but less opinionated and doesn't interfere with scrollback.
Probably goes without saying, but for anyone who doesn't know about it, `jq` is life changing, was kind of surprised not to see it. It's a sort of query language for querying JSON blobs. I use it almost every single day. It's indispensable.