Hmm... Lots of good discussion here already, but to answer the question you actually asked...
##NO.
NO.
No, you can't have consensus on what flag you should use for "link only answers", because as Tim notes you shouldn't always be flagging them, as George notes there's no "one size fits all" flag reason for them, and as Anna notes they're quickly becoming a mythical beast anyway.
I've written about this before... Twice... But I'll try once more to make this crystal clear:
##Flags should describe a problem; "links" are not a problem.
Flags should describe a problem; "links" are not a problem.
There are other sorts of flags that do describe the sort of problems often indicated by link-heavy answers:
Shameless self-promotion? Spam!
Makes no effort to answer the question (perhaps an answer lies at the end of the link; perhaps it does not)? Not an answer
Links to w3schools? Very Low Quality! Ha ha, just kidding. No, seriously, don't flag those. Edit in a link to better documentation.
Something else? Describe that in your custom message to the moderator. And by "describe" I mean "in more than three words" - if you're gonna complain about what is essentially an answer that is unhelpfully terse, then it behooves you to not commit the same sin while doing so.
##Oh, yeah... And none of this even matters.
Oh, yeah... And none of this even matters.
So, yeah - the guidance on those two declined flags wasn't terribly helpful. In defense of the mods writing those decline reasons, they at least bothered to type out more than three words. There's a length-limit there too, and face it: mods on SO are busy. This is one of those unfortunate cases where something written in haste ends up exploding and wasting far more time than it would otherwise.
See... Most answers flagged as "link only" are deleted... As are most answers flagged "Not an answer". They're deleted because they're lazy, unhelpful answers. Believe it or not, most of the "link only answer" flags declined are declined because between the time when they were flagged and the flag was handled, the author went back and fleshed out the answer a bit... Often in response to a helpful comment suggesting that he do so. 'magine that...
That's right: the best way to get your flag declined has nothing to do with the actual reason you give for flagging. Wanna make sure your flag stats never take a hit? Make sure you never give the author of the posts you're flagging any indication that their posts are crap and should be improved.
Of course, if you actually give a rat's ass about improving the content on the site, stop stressing over 3-word magic incantations and talk to people.