Link Bulk Downloader от Manuel

This add-on has a single goal: allow you to select any number of links from the current tab and and download them all in one click (instead of having to right click to "Save Link As..." on each of them!).

Usage is very simple, you click on the toolbar icon, click on "Show Selection" to show a checkbox next to each link in the page, select the links you want to download and click "Download Selected" on the toolbar menu. After you're done, click "Hide Selection" to remove the checkboxes from the page.