The most common and most likely answer to this crossword clue is the 8 letter word PLOTTERS
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More clues leading to the result PLOTTERS
Buddy explains!

The straight part
We know that "They have schemes/they map out on paper" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they have schemes/they map out on paper = plotters.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PLOTTERS mean?
PLOTTERS noun- A person who plots.
- An output device that draws graphs and other pictorial images on paper, sometimes using attached pens.
- An instrument used to mark or find the position of a vessel on a chart.