Compared to many of your stories, I've been pretty lucky over the years, but I've had two major extinction events, where I lost a lot of plants, both times it was primarily phrags.
First extinction event was my introduction to erwinia. This was probably in the 2004 - 2005 range, in the dead of winter if memory serves correct. It seemed like one day, my collection was perfectly fine, two or three days later, nearly all paphs and phrags had some level of infection. It destroyed almost all of my seedlings and took a couple years for the blooming sized plants to recover. I don't specifically recall which plants died, I just know that some were immediately total losses, some simply failed to recover.
The second extinction event was due to my neglect. That was around 2008 or 2009. I was working and going to school full time, plus getting adjusted to new growing conditions, which were already suboptimal, and having to cut back on light and heat because I could barely pay the bills. Over the course of a few months, I lost a lot of plants. Many of these were mature, multi-growth specimens. This second extinction was the one I regret the most. I lost the only plant I've ever had awarded, a phrag. I also lost a particularly nice phrag schlimii. There were many others as well, too many to name or count. Surprisingly, the phrags dealt better with neglect than the paphs did. Or at least I should say, the phrags were easier to recover than the paphs.
The most expensive loss, though was a Phrag. Fritz Schomburg. I bought a near blooming sized plant back when they were really expensive (for me expensive is $100+). It did really well for me, made me feel like a real pro. One winter, it looked particularly promising. It had two growths, one mature, the other new. The base of the oldest growth started swelling, a sure sign it might bloom. And then my roommate's cat decided it was delicious. When I found the plant, what foliage wasn't eaten was just a mushy mess. Needless to say, the plant didn't survive, not for lack of trying.