Some chocolates will do. Kids are easy to please anyway. I'm sure they'll love it!

Get some DC themed fidget spinners for anyone over the age 4.

Get DC themed board books for anyone under 4..

How about books that are about the D.C. area, like "Good Night, DC" or "I Dissent"? Or D.C.-themed/Smithsonian t-shirts and onesies? Cap it off with a couple boxes of Bergers cookies and some Old Bay seasoning?

Books and t-shirts that are slightly too big for the older kids.

I like books for this kind of thing. You'd pick different ones for the infants than the 8 YO, obviously, but they're easy to pack, unlikely to be damaged, and if you pick less obvious ones (no Goodnight Moon!), you're not likely to repeat ones in their collection. If you do, books are easy to pass along and donate, so the receiving parents don't feel like they have to keep this thing they don't like to keep me happy.

We'll be going back to our home town to visit 5-6 families/friends who we haven't seen in a few years. What's a good gift idea that I can just buy in bulk without picking up a bunch of custom lego sets or anything bulky as a part of our visit?

Some friends have 1 and infants, some have 3 kids with a range from 1-8years. Or should I just bring food or something? This is one of our first big trips back home with the kids so haven't really had to deal with this before. Any suggestions welcome!