For Drupal 8, Module Builder is undergoing some big changes. It still builds hooks, a README file, an api.php file, permissions, an admin settings form, but now also builds plugins, services, routing items, and its ability to scan your codebase to learn about hooks invented by any of your modules is now extended to plugin types too. And it's actually been available for Drupal 8 for quite some time, but up till now only as the Drush plugin version.
I've now released the D8 version of the module, so you can use an admin UI in Drupal which lets you select the components you want in a form. Unlike Drupal 7 though, the options you enter for your module to generate are stored in a config entity, so you can generate code and then go back and tweak the settings and generate it again, as often as you like.
The big change isn't any of these though. The big change is that Module Builder is being split up.