Not sure which website would have that information. However, from the top of my head (the number of alternates, NOT including originals):
Keep Yourself Alive (has at least 3 other versions)
Liar (1)
Seven Seas Of Rhye (2)
Killer Queen (1)
Stone Cold Crazy (1)
Bohemian Rhapsody (3)
I'm In Love With My Car (1)
Good Old Fashioned Lover Boy (1)
We Will Rock You (2)
We Are The Champions (1)
Bicycle Race (2)
Crazy Little Thing Called Love (2)
Another One Bites The Dust (1)
Flash (1)
Under Pressure (2, although this includes the '99 "Rah" version)
Radio Ga Ga (I *think* the video EP differs slightly from the "Flix" version)
One Vision (2)
Who Wants To Live Forever (2)
Innuendo (3)
The Show Must Go On (1)
These Are The Days Of Our Lives (3)
Heaven For Everyone (2)
Let Me Live (1)
A Winter's Tale (2)
No-one But You (1)
As I say, that's from the top of my head....it's not 100% I know, but it may give you an idea. Remember, the figures are for the number of alternates I know of, and don't include the originals.
I had NO idea there were so many 'different' versions of videos I've seen countless times.
The version of Breakthru on Greatest Flix II is DIFFERENT from the one on the Greatest Video Hits 2 DVD release?? Really? Friends Will Be Friends is different??
Damn. Interesting...