Produced Narcos around unknown quantity of colourful writers (7)
I believe the answer is:
crayons
'colourful writers' is the definition.
Although both the answer and definition are plural nouns, I cannot see how they can define each other.
'produced narcos around unknown quantity' is the wordplay.
'produced' is an anagram indicator.
'around' indicates putting letters inside.
'unknown quantity' becomes 'y' (algebra).
'narcos' with letters rearranged gives 'craons'.
'craons' enclosing 'y' is 'CRAYONS'.
'of' is the link.
Can you help me to learn more?
(Other definitions for crayons that I've seen before include "Wax pencils" , "colours" , "Coloured writing sticks" , "Coloured sticks for drawing" .)