Scanrand

Scanrand : An unusually fast stateless network service and topology discovery system
Scanrand is a stateless host-discovery and port-scanner similar in design to Unicornscan. It trades off reliability for amazingly fast speeds and uses cryptographic techniques to prevent attackers from manipulating scan results. This utility is a part of a software package called Paketto Keiretsu, which was written by Dan Kaminsky. Scanrand and Paketto are no longer actively maintained, but the latest released version can still be found at DoxPara.Com.

Unicornscan

Unicornscan : Not your mother’s port scanner
Unicornscan is an attempt at a User-land Distributed TCP/IP stack for information gathering and correlation. It is intended to provide a researcher a superior interface for introducing a stimulus into and measuring a response from a TCP/IP enabled device or network. Some of its features include asynchronous stateless TCP scanning with all variations of TCP flags, asynchronous stateless TCP banner grabbing, and active/passive remote OS, application, and component identification by analyzing responses. Like Scanrand, it isn’t for the faint of heart.

Angry IP Scanner

Angry IP Scanner : IP address and port scanner
Angry IP Scanner is a small open source Java application which performs host discovery (“ping scan”) and port scans. The old 2.x release was Windows-only, but the new 3.X series runs on Linux, Mac, or Windows as long as Java is installed. Version 3.X omits the vampire zebra logo. As with all connect()-based scanners, performance on Windows XP SP2 and Vista can be poor due to limitations added to tcpip.sys. The Angry FAQ provides details and workarounds. A short review was posted to nmap-dev.