MaikelM

Manage and display links on a WordPress site. Plugin uses custom types, so exporting is very easy. 
To display links in a post or page use the following short tags:
[links cat=”name of category”]
[SHOWLINKS] for displaying all links
A simple option to export links per category is possible using the overview screen: 
Click “All Link Items” -> Click on the link Category you want to export -> [OPTIONAL, but recommended] Select “Title” to alphabetize your export list -> Select “Bulk actions” and chose the Export to xHTML -> Click “Apply” Now you can save you selection. Use pandoc.org to convert your selection to markdown or another format if needed.
This Plugin has a “broken link” check functionality. 
The Broken checks can take a while with a significant number of links. The screen stays blanc during progress. note: No progress bar is shown.
See https://www.bm-support.org/innovation-links/ for a live demo.
How does it work? 
This module makes use of Custom Post Types with non hierarchical catalogue option. So you can give links one or multiple tags. 
Tags works great for retrieving or exporting only certain types of links. 
If all tags for a link are deleted, the link still exist. This is default WP functionality. Since this plugin in built on using default wordpress hooks, 
exporting and importing links can be done used as with post or pages.

Simple Link Library

Manage your link collection in a simple way.

Robert Heller

This WordPress plugin started as a portable, cross-platform system that 
the Wendell Free Library could use as a transition system from its current 
paper card based circulation system to the system that will eventually 
be rolled out by the regional library system. It has ‘morphed’ to a 
web-based successor to Deepwoods Software’s Home Librarian 3 system.
This plugin implements a simple and basic, web-based, library catalog 
and circulation system. There are short codes that can be added to 
pages of a WordPress site to search and display items in the library 
collection. And there are back-end (admin) pages that implement 
management of the collection, management of patrons (users) of the 
library, as well as implementing the functionality of a circulation 
desk.

WebLibrarian

A WordPress plugin that implements a basic library collection and
circulation system.

Simple Link Library vs WebLibrarian