Is there a document (pdf if any) that contains a comprehensive list of all shortcuts provided by AUCTeX? I mean a kind of AUCTEX Reference Card but for all shortcuts.
This question is related to my previous question:
Yes, there is an index of keybindings: it's in the index of the AUCTeX manual.
Note: I got to this index by googling "auctex manual", opening up the first hit, which is the manual, selecting the HTML option (although any of them would work), selecting "Indices," and finally selecting "Key Index."
Likewise, a google search for "AUCTEX reference card", the phrase you asked about, turns up quite a lot of them.
Please consider doing a little background research in the relevant manual. Although manuals vary in their comprehensiveness, and sometimes it's hard to know what to look for when the software does something astonishing, keybindings are generally pretty well documented.
You can run C-hb to see the current bindings.