I have moderated 20-30 in-person focus groups. It’s not my favorite method to use, but I feel comfortable planning and executing this type of study when it’s appropriate.
My favorite focus group ever was a focus group I did with little kids ages 4-8! Their parents were in the room too of course. We did a wizard of oz study with a projected character who would play games and do math with the kids. We had pre-programmed animations pre-configured for the furniture in our lab settings, and a confederate doing the voice from the other room. It was very challenging, but also a lot of fun and nothing builds confidence about managing adults like managing kids.