NPR's collection of D3 visualization templates. Not always great code, but well-tested and covers a range of responsive options. https://github.com/nprapps/dailygraphics-templates/
Aaron Williams at the Post has been posting about his workflow using D3 and Observable to prototype visualizations - https://twitter.com/aboutaaron/status/1107697344944975872
Thomas Wilburn book about doing dataviz and interactive journalism without using libraries like D3 Aaron Colby Williams @aboutaaron - https://thomaswilburn.github.io/viz-book/
@observablehq is my go-to tool for quickly sketching ideas w/o a full dev setup. I was able to share sketches (privately!) and iterate as the story and designed evolved. Both graphics started as forks of a notebook I use for almost all my Observable work https://observablehq.com/@aboutaaron/setup-page
Nadieh Bremer's list of data visualization resources, (which has a list of d3.js tutorials in addition to links to a bunch of other resources)
Tutorial on making a "first bar chart" for the Chicago Data Viz Community meetup by Mollie Pettit: Github repo here
D3.js Data Visualization Fundamentals by Lars Versphol
Javascript for Cats - Introduction for New Programmers
Web Basics and D3 Data Viz tutorials by Columbia University Data Journalism professor