Conference proceedings are a part of grey literature and can help add to your research. Topics covered at conferences usually cover current topics and are associated with the presenters' research. Make sure to look at the current conference offerings as well as past conferences. Sometimes past conferences are recorded or you can locate slides or notes from the presentations. If a speaker presents a topic you are interested in, look to see if you can find current or past articles they've written. You can even reach out to the presenter to see if they will discuss their presentation or research.