FSK441, designed to support communication using very brief “pings” from meteor trails in the ionosphere;
JT6M, also for meteor scatter, but especially optimized for the 6-metre band;
JT65, ideal for extremely weak but slowly varying signals such as those found on troposcatter and Earth-Moon-Earth (EME) paths;
EME Echo mode for detecting and measuring your own echoes from the moon. The program also offers a Measure mode for testing Sun noise and the like, and an EME Calculator to help you estimate the strength of your own and other stations’ echoes from the moon. If you have a desire to study the internal workings of WSJT and perhaps contribute to its development, a package of the critical source code is now available.
WSPR (pronounced "whisper") stands for "Weak Signal Propagation Reporter." This program implements transmitting and receiving for a digital soundcard mode usable with extremely weak signals.