Earlier quoted context omitted.
"Creative" is a well established commonly used term from the publidging and advertising worlds. Definition #2 at https://en.m.wiktionary.org/wiki/creative#Noun
Your definition defines it as an uncountable noun (like bread - a slice of bread - a loaf of bread, not "give me two breads"). But below in this thread I asked for example usages and the person I asked said: >"We have to work on the creatives to show to the client next week." That does not match the definition you just linked. https://en.m.wiktionary.org/wiki/creative#Noun it says "creatives" are people "some of the…
"Creative" as a noun meaning content shown in a single advertisement with the plural of "creatives" is definitely in use in the places I've worked, which include a magazine/traditional publisher and a silicon valley tech company that has a large market share of the advertising industry.