Also the Lake Peigneur incident where a lake emptied into a mine due a drilling error. Not a dam breaking, but still a water disaster.
I remember reading about one in Italy about 40 years ago. The dam didn’t break, a landslide into the lake created a wave which went over the dam and flooded the valley. The people who lived near there then attacked the builders of another dam in the area.
No mention of the Buffalo Creek West Virginia disaster? As I recall, over 100 people died in that flooding, after a coal slurry drainage pond dam gave way.
If that’s the one I think it is, there is good video in a documentary. Amazing to watch for sure.