This guide is designed to bootstrap your project - it features first-stop or otherwise top resources for acquiring geospatial data, doing GIS work, or building geospatial applications. It is not an exhaustive directory of resources, but rather a concise and lean tool for those who are in need of some of the more common and reliable resources in GIS.
For those in need of more advanced help or more arcane resources, the Purdue Libraries GIS homepage is here.
Not that this guide isn't super fantastical, this link will fire off a search for other GIS/geospatial libguides from other institutions. You can refine the query by adding more terms, if you like (e.g. http://libguides.com/community.php?m=s&it=1&search=geospatial+elevation)