DevOps

Version Control

Git - Best, most ubiquitous version control technology in the world, to the best of my knowledge. It was developed by Linus Torvalds himself to manage Linux core contributions in the late 90's.
Fossil SCM - a new-ish contender to Git which is fairly compelling for a variety of technological and workflow reasons. Something to watch. But, for now, stick with Git.
A nice Git Tutorial from Github.
GitHub - Amazing universe of open-source software. Unlimited hosting of open-source repositories. Has issue, milestone, and project tracking. Has project wikis. Integrates with everything.
Bitbucket - Like GitHub, but unlimited hosting for private repositories, which can be nice for internal or sensitive State projects. Also has wikis and its own CI/CD technology called Pipelines built-in. Before it was cancelled as a project by someone to remain nameless, ODE was going to convert all existing Version Control systems in the State (of which there are nine, costing over $100,000 annually) to Git/Bitbucket Enterprise. Someday...
CodeGiant - New entrant hoping to offer a better-designed experience.

GitHub Desktop - simple, nice-looking, approachable client.
SourceTree - from Atlassian, makers of Bitbucket.
GitKraken - beautifully designed Git Client.
Original Git Bash Shell - for ballers. This actually comes with GitHub Desktop and SourceTree, so usually doesn't have to be downloaded separately.

Vagrant - easy to spin up virtual machines, configurable via simple YAML files.
Docker - THE base container technology. Easy to configure, stitch together, and lock down. Preferable these days to Vagrant.
- This is the official Docker tutorial.
- Just enough Docker to be Dangerous is a good intro tutorial, as well, by Sean Kross.
Kubernetes - The industry-standard way to scale out and coordinate tons of Docker images working together. Kind of amazing, really.
Scotch Box - Pre-configured Vagrant box. Very nice - everything just spins up and works.