Ten Unicums in Tanakh

Some of these are curious because they appear at all, some because they appear only once.

Pharoah's birthday: (Gen. 40:20). The only birthday celebration.
1. Balaam: The only non-Jewish prophet.
2. Balaam's ass: The only talking animal (other than the snake in the Garden of Eden, who is in a different category of myth).
3. Michal the daugher of Saul: The only named woman explicitly said to love someone (David).
4. Samuel's ghost:: The only ghost. The witch of En Dor is the only named witch.
5. Michal the daugher of Saul: The only named woman explicitly said to despise someone (David).
6. Achitophel: The only suicide.
7. Sacrifice of firstborn son of the King of Moabi: Only human sacrifice of an identified person. Odder still, it's a successful human sacrifice; the King of Moab goes on to win the battle (2 Kings 3:27).
8. Speech by worshippers of Astarte to Jeremiah: Only strongly worded defense of idolatry.

   Thereupon they answered Jeremiah—all the men who knew that their wives made offerings to other gods; all the women present, a large gathering; and all the people who lived in Pathros in the land of Egypt: On the contrary, we will do deverything that we have vowed-d—to make offerings to the Queen of Heaven and to pour libations to her, as we used to do,e we and our fathers, our kings and our officials, in the towns of Judah and the streets of Jerusalem. For then we had plenty to eat, we were well-off, and suffered no misfortune. But ever since we stopped making offerings to the Queen of Heaven and pouring libations to her, we have lacked everything, and we have been consumed by the sword and by famine. And when we make offerings to the Queen of Heaven and pour libations to her, is it without our husbands’ approval that we have made cakes fin her likeness-f and poured libations to her?”