For the current (old?) quizzes the API makes it easy to identify courses that contain quizzes. However, with New Quizzes there is currently no way to use the Canvas API to determine which courses are using New Quizzes or a list of quizzes from a course.
There is also a “external_tool_tag_attributes” field on the Assignments API endpoint that can be used to identify the assignments using New Quizzes, but there doesn’t appear to be any way to filter an API call by that field and looping through all courses/assignments would be cumbersome.
A list of courses using New Quizzes can be found using Canvas data, but it would be much easier (and without the delay that comes with Canvas data) to have it available through the API.
As we work on exploring New Quizzes alongside current quizzes over the next period of time. We currently have a process in place to be able to extend time on quizzes for students with disabilities. However, we now have some faculty using New Quizzes which offers a way to extend time on quizzes, but without a way to easily identify those courses it is difficult to know when we need to add time to quizzes in a different way that we do with the current quizzes.