HTML and CSS Courses | Udemy
Free HTML and CSS courses on Udemy.
Learn HTML | Interactive tutorial from web.dev
This HTML course for web developers provides a solid overview for developers, from novice to expert level HTML.
Learn CSS | Codecademy
In this CSS tutorial, you’ll learn how to add CSS to visually transform HTML into eye-catching sites.
Learn HTML | Codecademy
Start at the beginning by learning HTML basics — an important foundation for building and editing web pages.
Intro to HTML/CSS | Khan Academy
If you like learning from videos, this series from Khan Academy is for you.
Course: Accessibility: How to Design for All | Interaction Design Foundation
Course: Accessible Documents: Word, PowerPoint, & Acrobat | WebAIM
Course: Introduction to Web Accessibility | edX
Web Accessibility Training Courses | Deque University
Designing and Teaching for Impact in Online Courses
This course could be a more visually effective, but on balance it's a decent example of ID principles like chunking content, checking for knowledge, and accessibility. BONUS: Lots of good ID info in the course itself.
Instructional Evaluation Service Course
This is an OER course on instruction design that, appropriately, is a reasonably good example of instructional design. I say reasonably because it could be better in terms of visual design and wayfinding.