When X is connecting to a particular piece of hardware, you can first use the NI Developer Zone search tool to see if NI has a VI you can use. Next, check with the manufacturer. Next, you can see if a third party has produced one by reading the listings on the Find All VIs site.
If you're still looking, post your question because many people have additional drivers that aren't published anywhere. When X is more general, there are several places to check for an immediate answer before posting your question:
1. NI Developer Zone Resource Library 2. NI Developer Zone - Developer Exchange 3. NI Example Programs Database 4. Find All VI's Project **
Number 1 is probably the easiest to use because it has categories, a search engine, and good VI descriptions. Number 4 has even more categories and the most complete set of content, but no search tools or VI descriptions. Number 3 still has some items that number 1 doesn't, but far fewer categories. Number 2 is still small and uncategorized but is slated for improvements. You probably should be able to find what you're looking for among these resources, but you may need to post your question if you can't find the answer yourself.