D3

Official D3 Site
Official D3 Wiki
D3 API Reference
Changes in D3 5.0
D3 Q&A Slack
D3 on Stack Overflow
Mike Bostock’s site
Mike Bostock on bl.ocks.org

Web Development

Mozilla Developer Network
DevDocs – Unified documentation on all web technologies

Git

Official git command line and GUI clients, official documentation
Simple guide for getting started with git
Setting up git
Understanding git conceptually
Pro Git (book by Scott Chacon and Ben Straub)
GitHub Client for Mac
GitHub Client for Windows
SourceTree for Mac and Windows
TortoiseGit for Windows

Data Sources

Government Data

UK Office for National Statistics
Census.gov
Data.gov
Utah Data
CDC Data
World Bank Catalog

Data by News Organizations

FiveThirtyEight Data
Guardian DataBlog

Other Data Collections

Awesome Public Datasets
StateMaster

Vis Web Sites & Blogs

Visualization Design Lab Website
Data Stories Podcast
Multiple Views Blog
eagereyes Blog
Gapminder
Flowing Data
Perceptual Edge
Visual Complexity