Hmm. Probably people's jobs and what's happening with them. Probably iPhones (someone has a new one, and everyone else - well most everyone else - has them). Probably my daughter's cats. Probably a few stories about Easter's when the kids were little. Probably vegan and/or vegetarian restaurants. Probably a few updates on anything new with some in-laws and/or cousins or closest friends. Probably anything particularly funny that anyone has recently run into somewhere (TV, YouTube, whatever). Probably the latest in computers and/or software. Probably a couple of causes that a few people are interested/involved in. Any books or movies anyone has run into recently. Probably a certain amount of political issues - not too much, but some. There'll probably be some sharing of pictures of people's recent trips, recent furniture purchases, and - again - one person's cats.
Most often at family gatherings there's a question or two that one of my grown kids has thought up to ask about either our family background, their grandparents, or one of their parents' childhoods. Sometimes there's a question or two that someone has saved to ask about something from their own childhood (usually something they partially remember and want some details filled in).
They probably won't talk much about the meal, but there'll be candy and fruit; so candy usually brings up talk of other candy anyone has ever liked as kids (or holidays when the same candy showed up), and there's most often talk about who likes which kind of fruit and anywhere anyone has been where fruit has been served in a particularly nice way. There'll probably be talk about different wines people have run into somewhere along the way. There's likely to be some talk about "the Boston music scene". Then there'll be stuff that's different from the usual kind of stuff, most likely.
Finally, one person (guess who) is very likely to bring up a couple of "adorable" or "delightful" little stories about what any one, or two, or three, of the grown kids did when they were babies, toddlers, or young preschoolers (but not embarrassing stories - cute ones). That one or two stories will get a laugh from their father, a little extra information/insight from the character(s) in the story; and then anyone who wasn't part of our family "back then" will likely share his own similar story.
Oh... and then someone will have to bring up something about the latest vs classic plastic eggs and any preferences. :)