Go because it's easy and simple, facilitates collaboration , and also it's fast, scalable, powerful.
Visual Studio Code because it has one of the most sophisticated Go language support plugins.
Vim because it's Vim
Git because it's Git
Docker and Docker Compose because it's quick and easy to have reproducible builds/tests with them
Arch Linux because Docker for Mac/Win is a disaster for the human nervous system, and Arch is the coolest Linux distro so far
Stack Overflow because of Copy-Paste Driven Development
JavaScript and Python when a something needs to be coded for yesterday
PhpStorm because it saves me like 300 "Ctrl+F" key strokes a minute
cURL because terminal all the way

My Stack