Does anyone know of a plugin for modx that will show all the pages that link to each document ID or would I have to create my own?
You could write a snippet for yourself. Use the code
$weblinkArray = $modx->getCollection('modWeblink',$criteria);
where $criteria
is the set of criteria, restrictions or constraints you want to set, like
$criteria = array(
'published' => 1,// this is optional, more parameters can be optionally added as well
)
This gives you an array of the documents that link. Further, you know how to access data of an array.