What is a good side dish to take to a potluck dinner, when you have no idea what the main course, which I assume will be provided, is?

I have a potluck dinner to attend tomorrow. There is no mention of what the main course will be. I don’t know if it will be some sort of turkey or ham, kind of in keeping with the time of the year, or some sort of barbecue or fried chicken or something. I sent an email asking what it was, got no response, and no one else seems to know either.

What is a good catch-all side dish I could take?