was expaceting more then 3 tools to be listed
Well..I made the above post while actually working on the machine to find possible rootkits/malware on it... doing a bit more survey using google fetched me the following tools..

1. Rootkit Hunter (mainly for Linux/ Free BSD distros).
2. chkrootkit (also for Linux/Free BSD)
3. UnHackMe (For Windows based machines)
4. Trojan Hunter

Though I am yet to try and analyze these tools but they serve as useful addition to the above list.