<p>On-topic:</p>

<ul>
<li><a href="http://stats.stackexchange.com/help/on-topic">Data collection</a>, i.e., <a href="http://meta.stats.stackexchange.com/questions/2528/why-is-data-collection-listed-as-on-topic-but-a-data-collection-question-was-cl">aspects of data-collection methods: sampling schemes, surveys, experimental design, etc</a>.</li>
<li><p><a href="http://meta.stats.stackexchange.com/questions/2096/questions-about-datasets-possible-exceptions">Statistical features and concepts of datasets</a>. Examples:</p>

<ol>
<li><a href="http://stats.stackexchange.com/questions/74776/what-aspects-of-the-iris-data-set-make-it-so-successful-as-an-example-teaching">What aspects of the &quot;Iris&quot; data set make it so successful as an example/teaching/test data set</a> </li>
<li><a href="http://stats.stackexchange.com/questions/109710/good-data-example-needed-with-covariate-affected-by-treatments">Good data example needed with covariate affected by treatments</a></li>
</ol></li>
<li><p><a href="http://stats.stackexchange.com/questions/173060/what-exactly-is-big-data/173063#173063">Large data</a>; relating to <a href="http://meta.stats.stackexchange.com/questions/2714/are-questions-related-to-big-data-on-topic-here">theoretical aspects of the data and implementation of algorithms over it</a>.</p></li>
</ul>

<p>Off-topic:</p>

<ul>
<li>Questions asking for <a href="http://stats.stackexchange.com/help/on-topic">particular datasets</a> are off-topic. The Stack Exchange site <a href="http://opendata.stackexchange.com/">Open Data</a> would likely be interested in fielding such questions.</li>
</ul>
