You can find a list of courses that will fulfill a requirement in a couple of different ways.
One way is to find the requirement/category in the "Track Progress" tab. Next, click on the three dots next to the title and you'll see a link to Search Qualifying Courses:
You can further refine the list to show Only with cleared prerequisites, to help you more easily see courses you can take right away.
Another way to search for courses that will fulfill a requirement is from your "Plan your Path" tab. The default view of this page shows the "Tentative List" in the right side menu, which lists all of the requirements that you haven't taken or added to your plan. Any course that appears with a dotted outline is a placeholder, meaning that it is a requirement that has several options of courses for that requirement. Clicking on the placeholder will bring up a list of courses that are able to count for that requirement. You can click on the placeholder from the tentative list directly, or add it to your plan to narrow the search by term.
Finally, you can also search for courses by requirement directly from the course search tab. Go to the "Explore Courses" tab on the left navigation menu, and use the "Counts for" filter to search by requirement. You can search for requirements for any program that you have in your Stellic plan - meaning any majors, minors, or other programs that you have added to your planner can be searched from here.