These are mostly free Drupal 8/9 training resources I have recommended in the past. The exception to the free part is the recommendation to subscribe to OSTraining.com, which unlocks a lot more content than the Drupal 8 courses that are free.
Paid Drupal 8/9 Training “Bootcamps”
DrupalEasy Drupal Career Online. Well respected (I sent my daughter through DrupalEasy Career Online when she decided to switch from energy and sustainability to development). 12 week on-line program done via Zoom/Google Hangouts. Two 3 ½ hour classes and a 4 hour lab session each week. Covers tools (e.g. git and composer), site building, and introductions to theming and module building. $3,400 tuition. https://www.drupaleasy.com/academy/dco/course-information
Debug Academy. I don’t know as much about Debug Academy. They offer a similar 13 week immersion course with the instructor available full time for 3 weeks after the course for follow up. There is an emphasis on building a functioning site/project. One of the projects the course attendees have worked on (in different sessions) is https://drupal.tv/. It does appear they offer hybrid online/in person programs. $3,600 tuition. https://debugacademy.com/
Drupal 8/9 Site Building
Drupal 8/9 Site Builder Certification
Acquia has a Site Builder Certification for both Drupal 7, Drupal 8 and Drupal 9 (separate exams). The Acquia Certified Drupal 8/9 Site Builder is a credential intended for professionals who build Drupal sites using core and contributed modules. This exam is designed to validate skills and knowledge of a Drupal Site Builder. This test focuses on knowledge of Drupal 8/9 and topic areas including Drupal features, content and user management, content modeling, site display, community and contributed projects, module and theme management, security and performance.
Information on the Site Builder Certification is at https://www.acquia.com/solutions/customer-success/acquia-certification. There is a Drupal 8 Site Builder Study Guide at https://acquia-academy.gitbook.io/study-guide-drupal-8-site-builder-exam/ and https://docs.acquia.com/certification/study-guides/d9-site-builder/
There is a part of the Acquia Site Builder exam that covers the community and using the issue queues. I found some free videos that should help make sure you are ready for that section.
https://drupalize.me/videos/drupal-community-demystified 1+ hour video
https://drupalize.me/videos/get-drupalorg-account 10 minute video
https://drupalize.me/videos/drupalorg-documentation 10 minute video
https://drupalize.me/videos/search-drupalorg 5 minute video
https://drupalize.me/videos/getting-started-issue-queue?p=1176 13 minute video
http://drupalladder.org/lesson/1d498fa2-d3e4-5754-9160-757d219e8032 documentation on Getting started in the issue queue
https://drupalize.me/videos/how-give-hug
https://www.drupal.org/issue-queue Use the issue queue
https://www.youtube.com/watch?v=8VKp7RBPOOY Drupal - Helping in the Issue Queues
https://www.youtube.com/watch?v=hRlXTinjs4o Drupal Dev Notes: How to start contributing to modules on drupal.org
https://www.youtube.com/watch?v=2_4_-Pfs5ww Reporting an issue: What developers really want to know
https://drupalize.me/videos/installing-and-using-dreditor
https://drupalize.me/videos/using-irc-internet-relay-chat
https://drupalize.me/series/learn-drupal-ladder
As a final step, I suggest you go to http://simplytest.me and start a Drupal 9 instance, expand the advanced fieldset and add the modules admin_toolbar and devel. When the site spins up, go to Extend and enable the admin_toolbar, devel_generate and ALL core modules EXCEPT experimental modules. Then go through each menu item and try the various options, also create a couple of content types using each field type, then have devel_generate create some content, then go back and try editing the field definitions, you should see the circumstances where settings can't be changed once content is created. Also look carefully at the text formats and how WYSIWYG is configured at a high level.
Online Training for Drupal 8
We use on-line training more than in-person training mostly because it is hard to get funding for in-person. Here's what I recommend to learn basic site building:
Make sure you have a drupal.org account, https://register.drupal.org/user/register. When you register, you start a clock that tracks how long you’ve had your account. That becomes part of your reputation later.
Install a local development environment on your computer. For long term development, I recommend a Docker based environment like DDEV, https://www.ddev.com/, or Lando, https://lando.dev/, but they are a lot harder to get running and require additional background not included in this site builder training. If you are not comfortable on the command line and only doing site building training to get started with Drupal, Acquia’s DevDesktop, https://dev.acquia.com/downloads, is a good, fully self contained option for either Windows or Mac. If you are using Linux, I assume you can install DDEV or Lando and should do it..
The key to getting the most out of this on-line training is to create a local site and follow along with the lessons, building the example site on your local environment. It is far too easy to say “I understand that” but then find out when you try doing it yourself you really didn’t understand one step which causes the site to not work as it should.
The following two classes are recommended in order listed. Both the OS Training and the YouTube URLs are listed. The classes are free either way. OS Training has a lot of additional classes, including more advanced Drupal, Wordpress, Joomla, PHP/MySQL, coding, etc. plus some supplementary material for the free classes (quizes and a certificate of completion). I encourage people to sign up for OS Training because it also helps fund additional courses. OS Training often (usually) has a special offer of $59/69 for a year’s access to all their material.
The Beginners Guide to Drupal 8
https://www.ostraining.com/class/d8-beginner
https://www.youtube.com/playlist?list=PLtaXuX0nEZk9MKY_ClWcPkGtOEGyLTyCO
Drupal 8 Site Building
https://www.ostraining.com/class/d8-site-building
https://www.youtube.com/playlist?list=PLtaXuX0nEZk9_p3OiVFV96FMQwPWklRiL
The Beginners Guide to Drupal 9 (enough different from the above Drupal 8 series that if you plan on using Drupal 9, use this course, although it is not free).
https://www.ostraining.com/class/drupal-9-explained-course/
Drupal 8 Layout Builder
https://www.ostraining.com/class/drupal-8-layout-builder/
How to Install Git
https://www.ostraining.com/class/how-to-install-git/ (paid section)
http://modulesunraveled.com/installing-git
How to Use Git and Version Control, Part 1
https://www.ostraining.com/class/git/ (paid section)
http://modulesunraveled.com/very-basics-git
How to Use Git and Version Control, Part 2
https://www.ostraining.com/class/git-2/ (paid section)
http://modulesunraveled.com/very-basics-git
Git Essential Training (89 videos, 6.5 hours) -- Paid
https://www.lynda.com/Git-tutorials/Git-Essential-Training-Basics-REVISION-2019-Q1/5030978-2.html
Git Branches Merges and Remotes -- Paid
https://www.lynda.com/Git-tutorials/Git-Branches-Merges-Remotes/5030980-2.html
Drupal 8 Composer and Configuration Management
https://www.ostraining.com/class/composer
https://modulesunraveled.com/drupal-8-composer-and-configuration-management
This class is a bit out of date and more oriented to developers, but still worth reviewing.
How to Use the Twig Template Engine
https://www.ostraining.com/class/twig/
How to Design Drupal 8 Themes
https://www.ostraining.com/class/d8-themes/
How to Develop Drupal 8 Modules
https://www.ostraining.com/class/d8-dev
Drupal 8/9 DevOps
Composer
drupal.org Composer documentation https://www.drupal.org/node/2718229
Common Problems and Solutions with Drupal + Composer https://www.jeffgeerling.com/blog/2017/composer-and-drupal-are-still-strange-bedfellows
Deprecated project (replaced by drupal/recommended-project) https://github.com/drupal-composer/drupal-project
Adding patches to Drupal composer projects https://github.com/cweagans/composer-patches
Composer in core initiative https://www.drupal.org/project/ideas/issues/2958021
Improve Composer Performance and Memory Usage https://www.jeffgeerling.com/blog/2018/make-composer-operations-drupal-way-faster-and-easier-on-ram
Composer Cheat Sheet for developers https://composer.json.jolicode.com/
Composer Documentation https://getcomposer.org/doc/
Building Drupal 8 Sites with Composer and Configuration Management https://www.youtube.com/watch?v=RzOt0LxNAec
DrupalCon Amsterdam 2019: Composer and Drupal: Past, Present and Future https://www.youtube.com/watch?v=ddPL91oHQdU
Composer 101 : Govern your Drupal project with Composer https://www.youtube.com/watch?v=3FOxjoVg2V0
Composer Tips/Tricks https://www.youtube.com/watch?v=H-1lMICDPy4
Composer 101 https://www.youtube.com/watch?v=TTNz8G9fxXY
Improving your Drupal 8 development workflow https://www.youtube.com/watch?v=Dq3tNi2ZTeE
Configuration Management
Configuration Management and Config Split Training by John Picozzi https://noti.st/johnpicozzi/Rlwyhv/configuration-management-config-split-basics-training
Building Drupal 8 Sites with Composer and Configuration Management https://www.youtube.com/watch?v=RzOt0LxNAec
Advanced Configuration Management in Drupal 8 https://www.youtube.com/watch?v=w0bhrmkaEVs
Using Config Split to Split Your Config Across Environments and Sites https://www.youtube.com/watch?v=rwKjVVhOHs4
Configuration Workflow D8 https://www.youtube.com/watch?v=fGq_xLmnvAU&list=PLsGrHy_lmfhSB6E7USUg9wgDel_xEd1qE&index=14
Testing
Testing -- Behat
Testing Your Drupal Website just got easier with Behat (A comprehensive tutorial)
https://www.specbee.com/blogs/testing-your-drupal-website-just-got-easier-behat-comprehensive-tutorial
Automate Tests For Multiple Drupal Sites Using A Single Script
https://www.axelerant.com/resources/team-blog/automate-tests-for-multiple-drupal-sites-using-a-single-script?hss_channel=lcp-3142330https://www.axelerant.com/resources/team-blog/automate-tests-for-multiple-drupal-sites-using-a-single-script?hss_channel=lcp-3142330
Writing Good Gherkin Enables Good Test Automation
https://angiejones.tech/writing-good-gherkin-enables-good-test-automation/
Testing the 'Add user' and 'Edit account' forms in Drupal 8 with Behat
https://www.jeffgeerling.com/blog/2018/testing-add-user-and-edit-account-forms-drupal-8-behat
Logging in as an existing user in a Behat test with the Drupal Extension
https://www.jeffgeerling.com/blog/2018/logging-existing-user-behat-test-drupal-extension
Using Behat as a Webapp Automation Tool
https://drupal.tv/external-video/2019-04-12/drupalcon-seattle-2019-using-behat-webapp-automation-tool
The Drupaler's Guide to Behavior Driven Development (BDD) with Behat
https://drupal.tv/external-video/2018-04-29/drupalers-guide-behavior-driven-development-bdd-behat
DrupalCon Seattle 2019: Behavior-Driven Development in Drupal 8 with Behat
https://drupal.tv/external-video/2019-04-12/drupalcon-seattle-2019-behavior-driven-development-drupal-8-behat
From User Acceptance Testing to Automated Testing
https://drupal.tv/external-video/2018-11-19/user-acceptance-testing-automated-testing
Drupal 8/9 Back End Development
Caching
https://www.axelerant.com/resources/team-blog/drupal-8-quick-handbook-on-cache-api
Drupal 8 Caching: A Developer’s Guide, https://www.youtube.com/watch?v=eB4NWo5XwMY
Caching Strategies for Scaling Drupal: Common Missteps vs Best Practices [May 5, 2016], https://www.youtube.com/watch?v=o8OWEFXqAjU
Module Development
https://www.youtube.com/playlist?list=PLpVC00PAQQxHi-llE9Z8-Q747NYWpsq6t
https://www.youtube.com/watch?v=f_6_v1leFiE&list=PL598781B77C942533&index=268&t=0s
Drupal 8/9 Front End Development
Theming
https://www.youtube.com/playlist?list=PLpVC00PAQQxG0sW9YOueVgouRp4aj1bng
https://www.youtube.com/watch?v=OZRax-Njrlo&list=PL598781B77C942533&index=240&t=0s
Decoupled Drupal
https://www.youtube.com/playlist?list=PLpVC00PAQQxFEfiUV2mq4o7yq--SHozfX
https://www.youtube.com/playlist?list=PLpVC00PAQQxH9OVQUl66Bw46ULgp-pgxR
FlexBox (Important for Acquia Cohesion)
Tutorials
The Complete CSS Flex Box Tutorial, https://medium.com/@js_tut/the-complete-css-flex-box-tutorial-d17971950bdc
Flexbox, https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layout/Flexbox
CSS Flexbox, https://www.ostraining.com/blog/webdesign/css-flexbox-basic-concepts/
Learn CSS Flexbox in 3 Minutes, https://medium.com/learning-new-stuff/learn-css-flexbox-in-3-minutes-c616c7070672
A Complete Guide to Flexbox, https://css-tricks.com/snippets/css/a-guide-to-flexbox/
Video Training
Learn Flexbox for free, https://scrimba.com/g/gflexbox
What the Flexbox?, https://flexbox.io/
CSS Flexbox Course (48 min), https://www.youtube.com/watch?v=-Wlt8NRtOpo
CSS Full Course - Includes Flexbox and CSS Grid Tutorials (1 hr 25 min), https://www.youtube.com/watch?v=ieTHC78giGQ
Learn CSS FLEXBOX in 20 Minutes (21 minutes), https://www.youtube.com/watch?v=qqDH0T6K5gY
Acquia Products
Acquia Cloud
Product Demo, https://www.youtube.com/watch?v=29xPdVLKCzg
Extended Demo, https://www.youtube.com/playlist?list=PLEF58274FFA13C53B
Acquia Cloud Documentation, https://docs.acquia.com/acquia-cloud/
Acquia Cloud Pro certification study guide, https://acquia-academy.gitbook.io/acquia-study-guide-cloud-ui-pro-certification-exa/
Acquia Cloud Site Factory (ACSF)
Product Demo, https://www.youtube.com/watch?v=bw-_rE-J7pc
Tutorials (ignore Drupal Gardens at beginning) https://www.youtube.com/playlist?list=PLpVC00PAQQxGUVGPh3mmHJ5Q3ndbbF0TA
Site Governance https://www.youtube.com/watch?v=8v44hQL2AsY
Acquia Cloud Site Factory Documentation, https://docs.acquia.com/site-factory/
Acquia Search Documentation, https://docs.acquia.com/acquia-search/
Config Management for Drupal Multi-site and Distributions, https://www.youtube.com/watch?v=T0uNpkM1M9M
Acquia Academy Partner Classes, Acquia Cloud Site Factory Customer Onboarding
Acquia Cloud Site Factory Product Introduction, ID: E-7VRD21 (4 videos)
Acquia Cloud Site Factory: Navigating the Site Factory Interface, ID: E-E045KV (12 videos)
Acquia Cloud Site Factory: Code Management Concepts, ID: E-602KWV (8 videos)
Acquia Cloud Site Factory: Many Site Management with Site Factory, ID: E-E0JXM1 (1 video)
Acquia Cloud Site Factory: ACSF Governance, ID: E-D19EP1 (1 video)
Checklist for Migrating Sites to Acquia Cloud Site Factory, ID: E-7VRG21
Cohesion
Product Demo, https://www.youtube.com/watch?v=nMBGcBpAbCk
Product Documentation https://cohesiondocs.acquia.com/user-guide
Product Video Tutorial (pre-Acquia acquisition version) https://cohesiondocs.acquia.com/tutorials/getting-started-training-demo
Acquia Certified Site Studio Site Builder certification study guide, https://acquia-academy.gitbook.io/study-guide-acquia-certified-cohesion-site-builder/
Acquia Academy Partner Classes, Acquia Cohesion: Site Builder 6.x Onboarding
Making the Most of Acquia Support, ID: E-P0YDE0 (4 videos)
Acquia Cohesion Product Introduction, ID: E-E0JOD1 (3 videos), https://www.acquiaacademy.com/learn/course/449/site-studio-product-introduction
Planning for a Successful Cohesion Engagement, ID: E-YVMKR1 (2 downloads + 2 documentation pages), https://www.acquiaacademy.com/learn/course/495/planning-for-a-successful-site-studio-engagement
Acquia Cohesion 6.x Site Building, ID: E-E0J8D0 (20 videos, same as Product Video Tutorial above) https://www.acquiaacademy.com/learn/course/473/site-studio-6x-site-building
Acquia Cohesion 6.x User Guide, ID: E-YVM5RV (17 “lessons”, same as Product Documentation above)
Lightning
Product Demo, https://www.youtube.com/watch?v=SNI23mWJunI
https://www.youtube.com/playlist?list=PLpVC00PAQQxG_Rv3DtrZtz_fdxGVb5EYL
https://www.youtube.com/watch?v=NOYnMGlylvI&list=PL598781B77C942533&index=254&t=0s
Packt Publications Books and Videos
https://www.packtpub.com/web-development/drupal-9-module-development-third-edition
https://www.packtpub.com/web-development/drupal-8-theming-twig
https://www.packtpub.com/web-development/mastering-drupal-8
https://www.packtpub.com/web-development/drupal-8-development-cookbook-second-edition
https://www.packtpub.com/web-development/learning-drupal-8
https://www.packtpub.com/web-development/mastering-drupal-8-views
https://www.packtpub.com/web-development/drupal-8-blueprints
https://www.packtpub.com/product/mastering-drupal-8-development-video/9781787124493 (video)
https://www.packtpub.com/product/drupal-8-for-beginners-video/9781787122895 (video)
https://www.packtpub.com/product/drupal-8-efficient-application-development/9781788299312 (video)
https://www.packtpub.com/product/drupal-8-development-solutions-video/9781786469939 (video)