Looking for plugin that allows people to search and filter within a page

We’ve created a collection of resources (some of which are pages on our site, some of which are PDFs, and some of which are off-site), and we want to create a page where people can better access them. We need a plugin that allows people to search and filter the resources on the page.

Basically, we’re looking for something that does what this page does, for a page that looks likes this. (The second link is to our website; the first page is another organization we’re emulating.)

Any suggestions? Knowledge base plugins have come the closest to giving me what I’m looking for, but they’re all geared toward organizing collections of articles that are all in one place on the site.

The page I need help with: [log in to see the link]