KSnapshot is a KDE snapshot tool with many features.
Xwpick lets you pick an image from an arbitrary window or rectangular area of an X11-server and write it to a file in a variety of formats.
xgrabsc lets you grab arbitrary rectangular images from an X server and writes them to standard output in a variety of formats.
4. Motv (xawtv)
Deinterlacing plugin for xawtv/motv.