[Plugin: Now Reading Reloaded] How can I find the books I put on hold?

Without writing new templates that specifically pull their status, you can only view books that are on hold through the management console (they are at the very end).

Ex. Your library template has several of these:

<?php if( have_books('status=unread&num=-1') ) : ?>

where status= unread, reading, or read.

If you add another block with status=onhold, you should be able to spit out books with that status.