Having already stating my preference for the BECM/1e/2e fire-breather, it should come as no surprise that Samples #7 and #18 are my favorites of those provided.
That said, I find myself REALLY liking #9, holding the sword with its tail. My only note on this one would be to stretch/move the head of the dragon more over top of the tail/sword handle to make it a bit more obvious as an ampersand. The way it is now is very cool looking and definitely something I could see in A logo...but it does not, readily, lend itself to appearing as "&". Moving the head more directly in line/above the left edge would fix that, I think, from what I'm envisioning.
Giving that Latin is all but a dead language, I think the history of the "&" as "et" is really pretty irrelevant...interesting, yes, but irrelevant (unless you want to explain the origins of the ampersand to every person who ever sees it, which I doubt) and the samples that make an attempt at looking like a combined "e" and "t" will simply be lost on...well...just about everyone...looking more unnecessarily fiddly, if not sloppy, as an "&."
But yeah, original flame-thrower, #'s 7, 18, and 9 (revised as stated above) would be my picks.
Think that's all I have to say on ampersands. Which, admittedly, is more than I would have thought possible. hahaha.
--Steel Dragons