NOBODY tops 1980s Optimus Primus (not listed) in my book....though 'Kit' came pretty close.
This is because I'm fond of well charactered and well characticured (sp) intelligent objects that are as well functional and transportive. Hero being bonus to the initial construct/application.
HOWEVER...
Of the choices; I've a toss up between Batman and X-men a heavy lean on X-Men, depending on singular or plural aspects, ect (politically correct, blah). I don't know some of the others.
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"I'm sorry Katya, my dear, but where we come from, your what's known as a pet; a not quite human novelty. It's why we brought you.... It's nothing to be ashamed of, my dear, but here you are and here you'll sit."