I’ve brought wall calendars with photos of scenes or flowers in our state, candy, mac nuts, and coffee. They always seemed well-received.
I agree things from your state or region might be nice.
How much do you want to spend? That pewter, and those baskets upstream are on the pricey side.
Also, how many gifts do you plan to take?
A proof set from the U.S. Mint.
(OP here) These are all wonderful suggestions! I’m from the northeast, but my hunch is that maple syrup is no longer a novelty in the UK, and I’d like to keep the spending modest. I’m not even sure how many people there would be - could be 2-3 or it could be 25. (Not interested in bringing 25 gifts!)
On the books for kids, my young British relatives loved Make Way for Ducklings and Miss Rumphius.
Of course, I am from New England so they are regional for me also. 
How about T shirts?
https://store.metmuseum.org/tableware/dehn-spring-in-central-park-coasters/invt/80015709
https://store.metmuseum.org/tableware/louis-c-tiffany-favrile-coasters/invt/80023226
Maybe look on Etsy?
A bottle of good bourbon from the Duty free?
I know you said no food, but how about some quintessentially American Penzey’s spice mixes? You can get them in the bags for easy transport.
Things like Chesapeake Bay seafood seasoning, Mitchell Street Steak Seasoning, Chili 3000, Southwest Seasoning, et al
What about some new collector’s stamps from the post office? It’s been a while but W used to buy sets and they were obviously coming from American culture, like Looney Toons, national parks, etc. You can buy sheets or books for not too much, since the price is just face value.
The US mint sets mentioned previously are also pretty cool (I’ve bought a few). If they’re still available some of the state quarters would be perfect (or heck, just grab a handful from your coin jar), or you can get silver dollars and such. I got W’s father (lives overseas but a big US baseball fan) one of those awesome silver/gold baseball coins many years back. W loved it so much when it arrived, she pulled a Sheldon Cooper and said, “never mind him, I’m keeping this for myself!”
A couple of suggestions for the children:
- Stickers. American children who are about 5 like these (more than you might expect)
- Colorforms set. I really enjoyed these when I was about 7.
- Crayola makes some coloring books with markers that only work on the pages of the books. My great nephews (5 and 4) really enjoyed having these when we went out to eat.
- Activity type books for children–e.g., Pat the Bunny
- Pop-up books. One of the “classics” that my daughter and I both love is The Pop-up Mice of Mr. Brice, by Theo Le Sieg (Dr. Suess in disguise). This is out of print, but can sometimes be found on Amazon or Ebay. (Avoid the really pricy offerings). There is a board book which is not at all as good. The real thing has pull tabs, doors to open, rubber bands to strum, strings to tie . . . They both have a mouse named Quackenbush. Mr. Brown can moo, can you (Dr. Suess) is available in the UK, but it has one element that makes it a fun gift there, anyway. That is the page with the “puddle beetle paddle battle.” Your British relatives will often find this to be a tongue twister, while an American who (like I) pronounces it as (more or less) “puddle beedle paddle baddle” will have no trouble at all.
- Small stuffed minion?
For the adults, perhaps a DVD? I once gave a small sample of native copper to an overseas friend who is a chemist, and that was well received. I like the idea of coasters, in American designs or neutral ones. I like rocks and seashells. Refrigerator magnets? (Because it is never too soon to introduce your British relatives to the American art of cluttering up the refrigerator?)
We always took different snacks and chocolates and the children seemed to love it. (Costco sized boxes) Coming back we would bring those local things from the country we would visit.
A small original painting of a local scene by a local artist. That’s what my kids brought me from their travels last summer , and what we sent as a gift to D’s home stay host when she studied abroad. You can find them inexpensively at craft fairs featuring local artists.
I’ve found the gift shops at state park visitor centers are a good place to find local art/books/miscellaneous items. Lots of unique small gifts, many of which are locally produced. Usually a wide variety of children’s books featuring local flora and fauna. Not sure about the British, but our German friends seem to appreciate Native American themed gifts. Christmas ornaments are a good bet as they don’t take much space and bring memories of the gift giver when pulled out once a year.
I guess I’d ask you, what would you like, if they were coming to visit you, your kids, and a younger child?
I know you said no food but the if it were me I think I would bring American candy because it is cheap, easy and most every age will enjoy it. You might have to do some research to find out what we have here that they don’t have there. I know my friend used to love when she could get “real” Cadbury candy from England as opposed to the Cadbury here that was somehow different.
Having relatives that live overseas…I would recommend children’s books for the children. Their books are different from our USA books. I love reading their children’s books as much as they enjoy ours. As for the adults, I would say something like reusable bags with prints from maybe your state or something that you relate to. Most countries don’t use plastic bags and so they use reusable. With prints or a story from you, they would always have a conversation piece. I would also second the ornaments. My relatives love seeing our special USA ornaments especially the ones from hallmark.
Well…how about maple sugar candy. Way easier to transport than bottles of syrup. They are consumable and folks can eat them or not while you are all gathered.
I would not suggest something like art. My inlaws sent us art things from all of their travels. We called them the trip souvenir gifts…and most were never used. A total waste unless you really know their tastes.
I still think calendars with American scenes would be nice. Easy to carry…and when the year ends…poof…they are done. I should add…I got calendars for the following year at a drug store, of all places…for $2 each…and I took 20 with me for DD to give as gifts.
For the kids, Pez candy in fun dispensers would be a good gifts. And it actually says “Made in America” on the package
No maple anything, LOL! My D brought those maple candies (after hearing of leaking syrup disasters) to various friends in France and England and they thought they were way too sweet.
For return visits, we brought tea towels with scenes of our town on them. Everyone can use a tea towel. D’s French host mom loves cranberries (hard to find anywhere in Europe or the UK) so D brought her packs of Craisins. This was a gift based on personal knowledge, though. If you don’t know the people well, it’s best to get something that would be useful to anyone.
Dried tart cherries from American Spoon or one of the other Michigan cherry sources.
I have to say that I would have absolutely no interest in stamps, coins, and calendars. Tea towels and tote bags, yes. I have to agree that maple sugar candy is awfully sweet for anyone except a little kid. (I find this interesting, though, because as a former chocolatier I find most European-style chocolates (pralines) much to sweet. Except Maison du Chocolat, which has excellent flavors.)
No offense intended to any suggestions: obviously, each of us is going to have a different level of interest in various items.
The EU is threatening a trade war retaliation involving tariffs on bourbon and cranberries. Obviously, those things were selected to grig Paul Ryan and Mitch McConnell, but still…
Uniquely American and easily transportable foodstuffs would include wild rice, Penzey spice mixes, Dried Tart Cherries, and dried cranberries or craisins. Bourbon you should be able to get from the duty free, which means you don’t have to pack it. Include a recipe for a Manhattan.
I would normally say I wouldn’t be too interested in coins, but the UK is putting out a series of ten pence, one for each letter of the alphabet, with “quintessentially British” things on them. B is for Bond, James Bond. Q is for queuing! They look hilarious.
So what is quintessentially American? It could be western or native american themed, or it could be the Statue of Liberty, or even Disney or Hollywood. Hard to choose. I would go with something regional and easy to transport.
I think the world is full of the same stuff. Liquor always wins. Touristy tat is the same wherever you are. I wouldn’t cart anything, myself. Shops in the UK are probably more fabulous than in many suburban US areas.
Unless you can do irony, then it is all up for grabs. Touristy crap for everyone, with a big wink. A red Trump hat for the win.