Way too many things to tell. I was fortunate in that both my dad (the youngest son) and my mom (the oldest daughter) in their families by chance got the bulk of the good stuff. We just went through mom's estate sale and I got most of the good things beforehand, like grandma and grandpa's kitchen table, the china cabinets from both grandparents, etc. The few heirlooms (like a Singer sewing machine similar to that noted above) I didn't get ended up with siblings though. To top it off, I bought out my siblings and got to keep our 90 acre family farm.
I also got the genealogical files, like one of those folks above. Among them is a passport from France in the 1600s. It's wrapped up and safe, so I'm not pulling it out for a photo. Here are a few things I can share:
My grandfather's Browning shotgun, which he bought around 1925 for $18 specifically to shoot a chickenhawk that was preying on his birds. I also have 2 .22 rifles he owned.
My grandmother's diaries, from the late 1920s to the mid 1960s. For the period that she's dating my grandfather, she ends the message with abbreviations, which my mom eventually figured out were codes for what they did while sitting on the porch or whatever. She would also sometimes write: "Joe very bad tonight." (Joe being grandpa). I can only imagine what "bad" means.
Also her crank record player from the 20s and most of her 78 RPM records.
My great grandfather's hand-built chair. Probably built in the late 1800s or early 1900s. Dog chewed a bit about 5 years ago, but it's fixable.
While I don't have a picture of him in that same chair, here's one of him (on the right), playing poker with cousins around the same time.