A few of my favorites:
Sometimes used to mark the end of an article or a press release. Its origin is debated, but the two numbers, standing alone, are always distinctive enough to denote finality. Its use goes beyond print. A CBS radio announcer, whose name I have forgotten, possibly Charles Osgood, signed off his daily reports with “And that is 30 for this edition.”
The dreaded kill fee. An amount you negotiate with your publisher in case your writing contract cannot be fulfilled. Often a tiny amount compared to the price in your original agreement, a kill fee might be invoked if you’ve revised your article many times but your editor is still dissatisfied with its suitability.
Illustrations. My Fort Brag printer used this term and I’ve always liked it. The photographs and diagrams I supplied were always collectively referred to by the term illos.
Writer speak for “to come.” TK is one variation of placeholder text, which can be any meaningless words or letters used to mark where additional writing must be added. See the illo below from a preliminary layout. The editor is showing me how much space I have to add new information.