Ask HN: Which tools increased your productivity the most?

For me it's been Gitpod (https://gitpod.io). It's like CI for development environments. It integrates with Git and lets me build my project continuously, and then create a containerized environment with the latest artifacts that I connect to with my IDE. I like it so much I decided to build a self-hosted alternative. It's at https://hocus.dev if you want to check it out.

What are yours?