Here’s a bibliography for the April 2017 meetup presentation about Flexbox and CSS Grid. More is being published on both of these topics all the time. You should definitely follow Rachel Andrew to keep up with Grid developments.
Want to know more about web accessibility? Here are some resources.
Find the WordPress site management tools we discussed at the February 2016 meetup here.
Here are the links I found while preparing for the April 2015 Meetup on Advanced Custom Fields and ACF Pro.
Links to useful resources for using Google Webmaster Tools with WordPress. You can even use Webmaster Tools with WordPress.com sites, though you can’t use Google Analytics on WordPress.com.