Similar to the Main Menu Block when on the front page of a Moodle site or using the Social Course Format, the Side Bar block maintained by Justin Filip of Remote-Learner provides a way to add activities and resources to a site and have them accessible from any of the topics that you might have. Even if you’re using all topics as their own page or if students are deep in webpages within your course. The block can be added as an always available resource to students.
According to the plugin database entry,
This block allows you to create separate activities and resources in a course that do not have to appear in course sections. The block can have multiple instances of itself within a course with each instance having its own unique group of activities and resources. Each instance can also have its own configured title.
It functions by creating course sections for each block instance, starting at a number beyond what is currently visible within the course. This prevents the activities from appearing to users who do not have permission to manage content within the course.
If you add extra section to a course using this block, a link will appear within the now-visible Side Bar block section that will execute a script to move the affected section (or sections when using multiple block instances) to be found after the last visible course section.
All resources and activities within a block can be edited and moved around just like normal activities when editing is turned on. Adding label resources allows you to add text to the blocks as well.
In a sense, this block combined the main menu block functions and HTML block functions into one block that can be used in a course.
Download it at https://moodle.org/plugins/view.php?plugin=block_side_bar. Checkout the screenshots below for how the sidebar works: