Are there tools that can be used to check for accessibility issues in a Canvas course?

Canvas is a learning management system (LMS) developed by Instructure. Like most LMSs, Instructure has actively worked to ensure Canvas is accessible to users with disabilities (for details, see the Canvas Accessibility page. However, even if an LMS is fully accessible, an instructor can offer an inaccessible course by creating inaccessible pages or uploading inaccessible content. 

CIRCL: A Promising Practice in Modeling and Promoting Accessibility

The Center for Innovative Research in Cyberlearning (CIRCL) is funded by the National Science Foundation (NSF) to work with cyberlearning-themed projects to support, synergize, and amplify their efforts. One of the ways CIRCL engages with the many targeted projects is through their dynamic website. The CIRCL site provides a place where new and existing projects can browse project descriptions, read perspectives from community members, and find resources.