I built 60 free developer tools that run entirely in your browser - what should I add next?

I've been building GenKit Lab, a set of 60 free developer tools in 10 categories: JSON, SQL, API (cURL converters), OpenAPI, regex, security (JWT, hashing), DevOps (Compose/Kubernetes/YAML validators), database helpers, AI/LLM utilities and general utilities.

Two design rules I held myself to: everything runs in your browser (nothing you paste is uploaded), and there's no sign-up, ads or cookie banner.

You can browse them all here: genkitlab.com/tools

What I'd love from you:

• Which tool do you reach for daily that you'd want to see done better here?
• If you try one, where does it fall short?

Disclosure: I'm the creator of GenKit Lab. Honest feedback (including "this is missing X") is the whole point of this post.