Thorondor
 

Is there any tale that tells of the fate of Thorondor, the 747 of the Elder Days? Did he go in to the west after the War of Wrath or did he (as I think) get killed by Ancalagon in the war?

I know of no refference about his fate. I also doubt he engaged Ancalagon personally. Even so, we must consider that The Eagle King was capable of wounding Melkor without, presumably, a single scratch on a feather. Since the Annals of Aman also implies that he was of the maiar, even his death would mean little, since maiar can arrange new bodies for themselves. If AAm is correct, then Thorondor probably ended in Aman.