GitHub - mediacurrent/theme_generator_8: Yeoman generator for Drupal Themes - lets you quickly set up a Drupal 8 theme with sensible defaults and best practices.
Using Core Themes in Drupal 8
Drupal 8 Theming Guide | Anubavam
Theme project | Drupal.org
Material base | Drupal.org
Top 10 Free Drupal Themes to Use in 2021 | Vardot Blog