Before anything, a disclaimer:

Never Break Dungeon Safety Protocols.

Rules and Regulations are written in blood. 

Make sure that blood is old and dry.

With that out of the way.

Fellow dungeon workers: Is there anything from a dungeon you worked at that you wish you could have saved? Just general interesting or cool-looking things that are not retrieved before the dungeon was killed?

(Please, do not post things that were taken out, this is specifically for things you did not. And also for dungeon-native things, not your tragically lost keepsake.)

For me, I have:

From a dungeon where everything was made from glass, there were some doors with a wood grain texture that looked absolutely beautiful. The extraction team did get a good load from that dungeon, but someone overlooked the doors. The extracted glass was entirely normal, so I could even have saved some to use for my house (I have tried to get someone to replicate it, but the result is never quite right).

Another is from a tropical dungeon with mix-and-match animals. Many genuinely dangerous monsters. There were these colorful-monkey things that looked engineered to be the next collectible toy craze. Probably not great pets, because they would scream very loudly when a dangerous monster was near, but the poor guys were otherwise pretty friendly and harmless.