I got tired of passing flags to Nightwatch to filter tests and looking through results to re-run failures. So I made an interactive CLI for all of that. I stopped using this once I moved to Cypress but even with Cypress' web interface, I feel something like Night Patrol would be a lot more productive.
Firebase Rules - https://github.com/jahed/firebase-rules
I didn't like how Firebase's RTDB rules were expressions in JSON strings so I built a library to build them using a lisp-like syntax to compose and re-use rules. Firebase also has its own rules language (Bolt) but I'd rather not learn and maintain yet another tool-specific language.
Promises - https://github.com/jahed/promises
This isn't a complete solution yet, I didn't get time to refine the API. But I really prefer using Promises as result types (a.k.a. either, left/right) rather than using async/await/try/catch. It's so much more powerful to write code in a way that doesn't care if your functions are async or sync. Again, kind of like a lisp, there's also power in not being tied to a language's keywords and being able to provide a more tailored vocabulary.