Not much yet on Chowhound about Union Market so I will get the ball rolling with this thread.
Union Market is off Florida Ave between 5th and 6th Sts, NE, and is an upscale market where you can mostly buy prepared foods to eat there or take away. Some places are just flat out restaurants, and some are take-out /markets.
I bought some green beans and herbs from the lone vegetable stand, Almaala Farms. Although the prices were not marked (you have to ask), it was not a complete ripoff.
Smoked bluefish and smoked tofu from Neopol Savory Smokery. Fish is exceptional, tofu is too intense.
French baguette (there are two other kinds of baguette in case you were wondering) from Lyon Bakery - very good.
Pint of peppermint Ice cream from Trickling Springs Creamery - very good.
There was a pop-up for Toki Underground, maybe today was the last day (?). They were making only one kind of ramen, shoyu (soy sauce), which they do not offer at their restaurant. Unfortunately the noodles were terribly gummy. The stock was very nice, and the soft boiled egg served in the ramen was perfect as was the pork belly. The noodles are very good at their restaurant, so maybe it was the setup at Union Market that thwarted them.
I believe Toki Underground will start serving lunch at their restaurant starting in a week (info courtesy of donrockwell.com). If it is the shoyu ramen, I hope at least they can fix the noodle problem.
It's an interesting place to visit, and I took the opportunity to visit A. Littieri on Morse St., NE for a few jars of Cento brand tomato products that I can't find elsewhere.