Have been a Visual Studio Code user since just after launch to the general public, having used the likes of Eclipse and Atom previously. Was amazed how mature it seemed off the bat and was super intrigued by the bootstrapped nature of it having been written/based on Electron/TypeScript, and of course being an open-source app from Microsoft. The features, plugin ecosystem and release frequency are very impressive. I do dev work on both Mac and Windows and don't use anything else now as far as IDEs go.
Have had gulp in my build toolbox for years now. Sure all the cool kids are using Webpack etc now as do I on some projects, but I love how easy it is to knock up a config, to load the dependencies and to script the simple tasks we do most often (concat, lint check, sass, etc..) with an easily repeatable config style and less opacity than some of the heavy hitters. Might not have the one-stop-shop that the 800lb gorillas have but still relevant on the tool-belt
In the past had always used Visio especially in a corporate environment but Lucidchart has been my go to for over 2 years now. The browser based experience is bang on, the UI not too cluttered, the range of symbols decent and the sharing and collaboration features are good enough. Like most web tools things may not sometimes feel as precise but when brain-storming or documenting something thats done it does the trick.
I use Postman across all of my stacks no matter the platform or the nature of the API being tested. The UI is excellent, the project sharing works well for teams, the built in test runner is great. The pricing is fair when it provides this much utility. A must have for team work in particular
I'm certainly no dev-ops guy and containers are not often on the radar for me currently so when I want a stable platform to prototype a web app on or to deploy to without fuss then Ubuntu is where I end up. Sure there may be other distros with a smaller footprint, or tighter security model, but my days of wrestling Makefiles is long gone so apt is about as deep as I go unless pushed. Ubuntu has the foundations of what I typically need out of the box.
Even tho this is a spec I guess as much as a tool I just couldn't do without Markdown for READMEs and docs in projects. No need for a CMS or wiki if you're dealing with a single page of content, or even a handful. Such a simple markup (sorry) language and so much tooling support available across IDEs, CLI/build stuff.