On the collecting thread, someone mentioned Brio train sets.
That is one thing I would NEVER sell - the Brio set - too much $$ and enjoyment and timeless enjoyment from it!
Also:
Marbleworks
Fisher-Price playsets with the “little people” - (mentioned as something I do collect)
Little Tikes big dollhouse with full house accessories (got rid of the Barbie dream house though!!)
American Girl dolls/accessories
Now, I will be happy to pass them on when my kids have homes and children. 
Agree on the Brio, the Fisher-Price sets ( the Discovery Cottage was the best first-birthday gift ever!), and the American Girl stuff.
Would add the maple kindergarten unit blocks, most of the wooden toys from the Hearthsong catalog (I avoided battery-operated toys like the plague).
And what I used to call the Desert Island Toys - those little hard plastic/rubber animals sold at quality toy stores, zoos, museums. My kids spent hours and hours playing with those.
Also at our house:
Legos
Lincoln Logs
Not going anywhere!
I think we might have sold some Playmobile. But still have some - I think! My kids didn’t enjoy Playmobile as much as other kids we knew.
Wooden unit block set and wooden marble runs, Groovy Girl dolls, American Girl dolls and lots and lots of books!
I have saved the Legos and Duplos (tons of those), have a little of Brio and Playmobil and saved that too. Also, a few wooden puzzles and some children’s books . And the Thomas the Tank Engine trains.
All the Thomas the Tank Engine trains (along with the Brio). My S got into Thomas long before it was widely available in the US. We had friend in England who would send us the latest engines. They were top quality. I also still have his Thomas fork and spoon set. If pressed, I think S could still recall the names, colors, and numbers of his favorite trains.
We had saved all of our kids’ toys. Last year, I downsized greatly when moving from the house my kids grew up in to a city apartment. Our old house had a very large basement where all this stuff was stored.
I got rid of all toys except:
American Girl dolls/clothes/accessories/furniture
full set of wooden building blocks
select stuffed animals
wooden train set that had been their dad’s as a kid
Beanie Baby collection
While not toys, we had tons of books and I culled through those and saved two large cartons’ worth of favorite kids’ books.
I also saved various baby/nursery paraphernalia including some decorative items…not a lot, but some.
We had saved their entire wardrobes but I gave all away except select baby and little girl outfits that were special such as certain dresses, gifts from grandparents, first outfits, first birthday, baby sweaters knit by grandmother, etc.
Saved a few other items like wooden rocking horse, first pair of skis, rocking chair they were rocked in as babies, and the like. And certain personal artifacts from their rooms and their youth.
No grandchildren yet, but we’ve got the stuff, LOL.
The Duplo, Lego, Fisher Price Little people (at least the ones that survived three rough boys) and a bunch of other toys I’ve been saving for 34 years. I now have grandchildren who come over to play with them and their mom remarked that those toys are way better than what you can get now. Does anybody remember the Buddy doll? And the stacking cubes. Don’t know who made it but my eldest got it as a first birthday present and it’s my grandson’s favorite.
I wish I had kept even more. Although some we got rid of because of the condition, not because no room to store.
Brio Train
Legos (and all the directions to assemble)
American Girl Doll…and all of her furniture, clothing, and stuff.
All the other toys…gone.
I got rid of everything except the wooden toys, rocking chair which was made for my son, the wood Thomas the Tank trains and rails and the electric train set my sister bought for him when he came. I am planning to loan these to my niece, who has a 1 1/2 yr. old to keep until he or any future kids she might have outgrows them. I will take them back and give to my son when/if he has children.
I also kept all the board books and the books he read when he got older. He ruined all the other books when he was a toddler.
There may be a few of the very good stuffed animals in a box but most of them I got rid of. He had hundreds of them, most of which had been my sister’s kids.
Legos
giant dinosaur set
Papo knights
http://www.thetoyking.com/papo-knights-papo-fantasy-figures.html?gclid=CjwKEAjwwZmsBRDOh7C6rKO8zkcSJABCusnb3dJ9CXHvaneHBJQb2Xjud4y2pmrzG36-wXFi95e48hoCP0Lw_wcB
basic wooden blocks
Rescue Heroes
books
@Mansfield - your post brings back so many memories. My S was also a huge Thomas the Tank Engine fan before it was popular in the U.S.
Brio
Lego/Duplo
Lionel electric train
Thomas the Tank Engine trains
American Girl/Bitty Baby
Wooden doll cradle
Wooden puzzles
Fisher Price school, airport and garage
And so many books.
Over the years, I’ve managed to part with many of the children’s books. At one time, I counted over 400 books. I’m down to about 50. I know I have to pare down some more, but it’s so hard. Too many favorites and fond memories.
We don’t have too many things, but the Brio set was the first thing that came to my mind.
We also have a set of Lionel trains that belonged to my brother and a set that belonged to me. My brother gave his train set to my son as his sons weren’t interested in them. My set is unique as it is the “girls’” set with a pink engine and pastel colored cars. My son has both sets.
I have no toys left from my childhood :(. We were a military family who moved around including abroad for a few years. I made sure I saved my kids first baby toys, favorite bedtime books as well as their art. S grew up during the second series of Star Wars movies and still has his collection of toys.
Thomas the Tank trains. We have the smaller metal ones. My son used to carry them around in a little napsack and play with them while we were waiting for dinner or at the doctors office.
@lilmom, that is also why I have saved some of my/my kids favorites - I have nothing from my childhood! I just don’t think my mom thought about saving anything.
I have kept a all of my kids’ favorite board books.
And even better, I still have a “fuzzy felt day in the hospital” from my childhood!
I have saved,
a Barbie Doll house
a play tea set.
My daughter took care of her dolls so the Barbies and Disney dolls are in a nice box.
Connect Four
Uno
A couple build a bears and all their clothes
I still have the foil balloons I received in the hospital when she was born.
I also have a binder with all her award certificates.
Her kindergarten and high school graduation cap/gown.
Her trophies and all the belts she received in Tae Kwon Do.
Several years ago with kids in college, I pulled out the Brio train set and put it up under the Christmas tree. We had an engine that ran on battery power - don’t know if they still make it, but after replacing the batteries, it ran like new. Over that Christmas break, my guys, Hubby included, spent more time with that Brio set than when toddlers, I think!
I saved T-Rex and Godzilla, who had some epic battles and may someday have more.
DH is an incurable packrat, and sentimental to boot, but I found a way to get rid of the Brio. DS liked it but didn’t love it, and just outgrew it. About that time a friend’s son was diagnosed with Autism. He loved loved loved the Brio at his therapists office, but his parents were young and stressed to provide that son with what he needed while keeping the rest of their young family cared for. I packed up all of our extensive Brio collection and took it to them, and even DH couldn’t get upset with me for it.