* Nuada is left handed - he lost his right arm during the fight with the Fir Bolg warrior Sreng, and we are told it was his shield arm, meaning his sword arm is his left arm
* Speaking of Nuada's arm, when it is healed it is the original flesh arm that is restored, which Miach acquires and holds against his body for six days, then strikes it with burnt bulrushes for another three. Which makes me wonder where the arm was for the intervening 7 years.
* When Miach heals Nauda's severed arm by replacing the silver prosthetic with the original flesh arm he is paid with the silver arm - which Nuada has been wearing and using for about 7 years
*The Lia Fail would cry out under every rightful king of Ireland - until Cu Chulain came along and hit it for not crying out under him. The Lia Fail is also the only one of the Four Treasures of the Tuatha De Danann that has no set owner. Each of the other three - cauldron, sword, and spear - belong to someone who is at one point High King of the Gods.
* one of Lugh's epithet's in the Lebor Gabala Erenn is "spear-slaughterous"; the great spear which is one of the four treasures of the Tuatha De Danann belongs to him.
* the Dagda's famous magic club doesn't actually belong to him - its only on loan. He obtained it while searching for a cure for his son Cermait who had been killed by Lugh for sleeping with Lugh's wife. He came across three men who were arguing over their inheritence which included a club which could kill at one end and revive at the other. The Dagda asked if he could borrow it and promptly used it to kill all three and revive his son, who shamed him into reviving the three men as well. After that he basically refused to return it, but an agreement was reached that he would permanently borrow it, giving the sun, moon, sea, and land as sureties against it.
* In several stories the Dagda is said to be "the king of the sidhe of Ireland" and it's implied he has authority over all the other fairy hills and their rulers.
* Although the Lebor Gabala Erenn gives an extensive list of the Tuatha De Danann and how they each died in myth, in the Cath Maige Tuired's list of battle deaths Macha is the only female listed among the warriors. In every account regardless of source she is always said to have died with Nuada at the hands of Balor of the Evil Eye.
* At the end of the Tain Bo Cuiligne the two bulls, who are actually cursed swineherds shape-changed, battle and kill each other. In this way the spell binding them is broken and they are freed.
* The famous Queen Medb of Connacht was killed by a piece of hard cheese - it was used like a sling-stone by a man avenging his mother's death. She was killed while bathing.
* In some versions of Cu Chulainn's death a crow lands near the hero who has been disemboweled and has tied himself to a pillar stone. The bird begins to peck at his entrails while he is still alive and Cu Chulainn laughs at it before dying.
References:
Lebor Gabala Erenn
Cath Maige Tuired Cunga
Cath Maige Tuired
How the Dagda Got His Magic Staff
Aided Meidbe
Aided Conculaind
Aislinge Oenguso
De Gabail in tSida