Q: Where is the Advanced Blocks add-on?
A: Advanced Blocks is a legacy add-on. It was replaced by the Show Blocks add-on. All old features were moved to the main CKEditor toolbar, so there is nothing to miss for. Documentation page for Advanced Blocks is being kept on the website for those users who still use this plugin.
We also have plans to return context menus to the plugin, but more cross-browser and cross-editor.
A number of related questions and answers can be found on the page of the corresponding Include CSS/JS add-on that is used to include Bootstrap/Foundation framework on the page.