I've got one for our draconic inspired friends.

Draconium Fever

Willsave DC 15, incubation day varies; see text

Hoard fever is found especially among the dragon touched races, races with dragon ancestry all the way back to 15 generations. Mind you that does not include Dragons themselves, though they once in a while display all the signs towards Hoard Fever. Apart form the dragon related races, Dwarves seem to develop a weakness to it without the relation to Dragons. They need to make a DC 13 ave, without their racial bonus against poisons and diseases.

When contracted, the sufferer gets a need to hoarding. Whenever a sufferer must relinquish control over a magic item, an item of power, money or other valuable things, the sufferer must make a DC 16 will save. Each time the sufferer succeeds the DC increases by 1 until the sufferer fails the save. Then the sufferer will do anything in his power to keep the aforementioned valuables to himself.

This affliction is purely mental and can only be cured through Wish and/or divine intervention, but not Limited Wish

And then something form our Bard Friend Ilyahir:

The Clap

Contact Fortsave DC 18, incubation period 1 week, during which you can spread the disease's effects.

The Clap is a disease often found among Bards, who, as a matter of promiscuity and handsome features have lots of contact with other people. This disease lowers the CHA of the diseased with 2d6 ability damage. The ability damage cannot be healed before the diseases has been cured with the Cure Diseases spell. The diseased can be identified by an incessant scratching of the crotch area (DC15 Willsave to resist for an hour)