ttyrpld is a multi-OS kernel-level TTY keylogger and screenlogger with (a)synchronous replay support. It runs on Linux, Solaris, FreeBSD, NetBSD and OpenBSD.
Strokey is a small hardware keyboard logger saving all keystrokes into an EEPROM memory for later investigation. The device may get attached to any PS/2-keyboard by intercepting the cable, or get placed directly inside for maximum invisibility.
KeyCounter is a tool for the tray-bar that helps you to get statistics about the useage of your computers keyboard, mouse and uptime. KeyCounter is not intended to work as a keylogger.
WindowsNT 5.x kernel driver designed to hide things like: processes, files, network connections and open ports. It also provides keylogger and communication with userspace tool that is authenticated with password.