Hel's Plagues

Probably the most famous plague in the traditional sense was in 1037E where the land sickened many who lived there also fell ill. This plague was eventually suppressed by the Healers of Sarenrae, a small sect of these Healers ended up founding the Hospice.
There are other plagues over the history of the Stoneheart valley, mostly crop blights. Some of these were almost certainly Telephos being a dick, but the rest were likely the result of Tsathogga and his glabrezus.
Hel's plagues are a little more interesting. She is a god of twisting corruption and in doing so turns the good creatures of the Valley into her servants. her plagues include
* 599E: Albino gnolls stalk and kill fishermen while they're ashore
* 602E: Giant giant ants destroy many crops
* 820E: Zombie hyenas mass around the foothills near Sandpoint
* 1030E: Death yaks outnumber sheep
* 1450E: Teleporting minotaurs attack coastal traffic
* 1669E: The trees walk. The trees kill
* 1670E: Dimension deer feast on the flesh of local villagers
* 1676E: Huge red bears attack loggers