Itrace is a program that implements traceroute(1) functionality using ICMP echo request packets. Therefore, it looks like you are just pinging your target while you traceroute there. It often helps tracing behind firewalls.
0trace is a hackish utility to run traceroute within an established TCP connection, thereby bypassing some stateful packet filters.
Tcptraceroute : A traceroute implementation using TCP packets
The problem is that with the widespread use of firewalls on the modern Internet, many of the packets that the conventional traceroute(8) sends out (ICMP echo or UDP) end up being filtered, making it impossible to completely trace the path to the destination. However, in many cases, these firewalls will permit inbound TCP packets to specific ports that hosts sitting behind the firewall are listening for connections on. By sending out TCP SYN packets instead of UDP or ICMP ECHO packets, tcptraceroute is able to bypass the most common firewall filters.
Firewalk : Advanced traceroute
Firewalk employs traceroute-like techniques to analyze IP packet responses to determine gateway ACL filters and map networks. This classic tool was rewritten from scratch in October 2002. Note that much or all of this functionality can also be performed by the Hping2 –traceroute option.