Mostly security and forensics tools which aren't mainstream. There aren't many practical, mainstream uses for "evil" hacker tools. Metasploit, Nmap, Nessus, Netstumbler, l0phtcrack, Aircrack, SATAN, Snort, Honeypot/Honeynet, John The Ripper, p0f, Ethereal/Wireshark, Hping2, Netcat, Dsniff. Like others have mentioned, any copyright-breaking tools like MPlayer, DeCSS, rtmpdump but there's no way to say these were written by "evil hackers" (more like hackers who just wanted to watch their own DVDs or download free public videos)