Review your list with the following characteristics in mind: age, class, disability, gender, geographical location, race, religion/belief, sexuality.
This isn't a checklist, you don't need content by or about every different group, but you should make sure you've included relevant perspectives from as many different groups as you can. You should also aim to include relevant work that takes different groups as the main focus or subject.
Pay attention to what is listed as core as opposed to recommended and wider reading. Are there any key authors, thinkers or theories that could be decentred and more dominance given to other perspectives or incorporating readings that challenge standard approaches in the discipline?
Alternative media can be an effective way to raise visibility across a breadth of voices that may otherwise be marginalized. Accessible formats will also accommodate varied learning needs, styles and environments.
If your discipline feels difficult to diversify, start conversations with students that recognise that and look for ways to view it through inclusive lenses such as inclusive pedagogies and frameworks. There is a useful guide from HEA Scotland has some suggestions for ways to embed diversity into your curriculum.