iColrot plugins are image displaying plugins. They all are based on same algorithm rotating thru color values of image, and displaying only part of the colors. By default they work in overlay + lens mode, so that under those plugins you may have other effects running uneffected.
iColrot is basic form of plugin.
iColrotslow is bit slower version of plugin, more suitable for slower music.
iColrotbeat is audio reactiong version. Colors are rotating only on beat, and speed of rotation and amount of colors shown depends on volume. For stronger effect, try changing volume scaling up.
Colrot plugins have been available since version 3.32