ProxyBroker
Asynchronous tool for finding and checking public proxy servers
...ProxyBroker can filter proxies based on criteria such as anonymity level, response time, country of origin, and DNS blacklist status. In addition to discovering and validating proxies, it can also function as a proxy server that distributes incoming requests across a rotating pool of working proxies. This capability allows users to route traffic through multiple proxies automatically, which can help with tasks.