Maybe you are already grokking Drupal 8's new configuration management system; maybe you've already absorbed D8's embrace of object-oriented code.
But that doesn't mean you should scoff at easy on-ramp introductions to Drupal 8. Solid overviews of Drupal 8 can be tremendously valuable when you're working on a team that includes non-technical members. They also come in handy when you are advocating in-house for D8 adoption.
Even if you can confidently riff on the benefits of Views in Core, you can probably help your case with some take-home materials. A new team member, or partner, or customer might appreciate something to print out and flip through on the plane. An entry-level D8 webinar might be just the thing to make a major migration seem a little less scary. You may even find them useful yourself, on those occasions when a project takes you to the outskirts of your Drupal expertise.
So for whatever purpose you want to point them towards, here is a curated selection of the best D8 overviews and intros.
The Ultimate Guide to Drupal 8
Of course, we at Acquia are partial to this guide, authored by our own Angie Byron, with a recent Drupal 8.1 update by Jeffrey A. "jam" McGuire. Particular strengths include sections on the Authoring Experience, the Mobile Experience, and Multilingual.
The guide also covers D8 from the point of view of Site Builders, Front-end Developers, and Back-end Developers. There's also an extensive section on Drupal 8 Core, and a final catch-all Q&A section.
Get it here: The Ultimate Guide to Drupal 8
Other Drupal 8 Introductory Resources from Acquia
Plenty of great D8 resources here, naturally, nicely organized around a scrolling jumping-off page.
OSTraining offers video training on all sorts of platforms, but Drupal is one of the team's strengths.
They are particularly good at video series, where you can, for example, build a Drupal 8 site while you learn, over the course of dozens of short videos.
A good place to start is OSTraining's free Drupal 8 Beginner Class videos on YouTube. There are 63 of these, all free, sponsored by Acquia. If you click around the OSTraining's YouTube playlists, you can find other free Drupal 8 video courses. If you want to go deeper, much more Drupal 8 goodness is available to subscribers, including topics such as Drupal 8 Theming and Drupal 8 Module Development. Currently, a month-long subscription is $25. You can also take advantage of a 2-day free trial so you can try before you buy.
An Acquia partner (we worked with them on Weather.com), Mediacurrent has been steadily publishing Drupal 8 resources for years. By now, they've got Drupal 8 content in a wide variety of categories. Among them:
The Chicago digital firm has published a strong intro ebook: Drupal 8: What You Need to Know. It has good overviews on Symfony and Object Oriented Programming. Also special sections for themers and marketers.
A few good D8 launchpads from the European digital services firm:
Collections of Drupal 8 Links & Resources
Did We Miss Anything?
Did we overlook an awesome D8 intro? Let us know in the comments and we'll check it out.