Hammerhead is a stress testing tool for Web sites. It initiates connections from multiple IP aliases and simulates a user from each alias. It is fully configurable, and there are numerous other options for creating problems with a site. Extensive data collection is also available.
ht://Check is a link checker derived from ht://Dig. It can retrieve information through HTTP/1.1 and store it in a MySQL database so that after a "crawl", ht://Check can return broken links, anchors not found, content-types, and HTTP status codes summaries. ht://Check also performs accessibility checks in accordance with the principles of the University of Toronto's Open Accessibility Checks (OAC) project, allowing users to discover site-wide barriers like images without proper alternatives, missing titles, etc. A PHP interface lets the user query and view the results directly via the Web.
LinkStatus is a tool for checking links in a Web page. It can search by depth, domain, or both. On a domain search, it's also possible to choose the search depth of URLs with foreign domains. It supports both Portuguese and English. For performance, it supports several simultaneous connections and tries to use the same connection for the same sequence of requests.