Although it doesn’t precisely answer the question, I landed here when searching for a way to get the collection of elements (potentially different tag names) that simply had a given attribute name (without filtering by attribute value). I found that the following worked well for me:
$("*[attr-name]")
Update:
It appears that the asterisk is not required, i.e. based on some basic tests, the following seems to be equivalent to the above (thanks to Matt for pointing this out):
$("[attr-name]")