I think that for all questions looking for particular data (as opposed to questions e.g. asking for the legal side of data) there should be a tag .g. data-hunt, or at least there should be a good convention for titles.
For me a question which is "Is there a complete data for X?" the right answer is "Yes." or "No.".
It's StackExchange. If someone wants to ask for sth, it is the best when it is done in a direct ways.
I would suggest using the same 'request' tag convention used by other sites… something like:
Feel free to suggest a better term for 'data', but I suggest following the basic [*-request] nomenclature.
I agree with you, I think there should be such a tag, to differentiate from some tools questions for example.
I would go more for dataset, simple data or even resources.
And I agree, all such questions may better have the title "What machine-readable data is available for ..." or "Which dataset provide information about ...".
I believe it would be easier to read through a list of "Where can I find X:" questions if there was a clear, minimalist title that provides key features required to identify data like:
Pigs (in space, pounds / year ) ?
With the units and scope in parantheses, and the question to indicate that they are looking. Perhaps there could be a "binocular" icon to represent "looking for".
Since many users will never see this post, when someone puts the phrase "I find" in the title field, a helpful notice could appear suggestings whatever conventions are adopted.
In addition, I think that there could be suggestions for relevant information that will help others provide useful answers, both in the text and tags. There is likely a set of key information (what where when ...) that could be requested, and this could make use of tags for categories and scopes of data.
Going off on a limb ... text and tags information could be used to search meta=-data of open data sets as the question is being typed ...
