The Nightcrawlers of the Marvel universe

Hey to all the nightcrawler fans out there.
So if you follow marvel closely, you get to find out that there are many universes/earths in which there are different versions of our marvel heroes. This has been a part of the marvel universe since pretty much the beginning of time.

So I've always wondered, how many versions of Nightcrawler are out there? I could never pin point them all and know quite a few.
Which ones do you guys know of?
Which one or ones are your favorite(s)?
And why?
I would love to know and see where the conversation would go on the subject