QuickMark allows you to set the raid target icon of units quickly rather than having to go through the right-click menu or create keybindings.

usage: /qm [s, show | h, hide | t, toggle | hor horizontal | vert vertical | f flip | l lock | u unlock | at autotoggle | scale <percentage>]
    s, show            shows the user interface
    h, hide            hides the user interface
    t, toggle          shows or hides the user interface depending on if it was hidden or shown respectively
    hor, horizontal    sets the layout to be horizontal
    vert, vertical     sets the layout to be vertical
    f, flip            inverts the layout
    l, lock            locks the user interface
    u, unlock          unlocks the user interface
    at, autotoggle          toggles autotoggling which shows the user interface only when in a party or raid
    scale scaleFactory scales the user interface using the scaleFactor.  The default scale is 1.0