The phrase "a storeroom of" is correct and usable in written English.
It can be used to describe a space or area designated for storing items or materials, often implying a collection of various things.
Example: "The old house had a storeroom of forgotten treasures, filled with dusty books and antique furniture."
Alternatives: "a storage area of" or "a repository of".
It prompted New York Times critic Brooks Atkinson to declare "it has been assembled from a storeroom of spare parts".
Nearly a half century after Dior's initial triumph, I sit in a storeroom of the Metropolitan Museum's Costume Institute, admiring a creation of his called Chérie.
Recovered in 1896 from a storeroom of the Ben Ezra synagogue in Old Cairo, this cache of documents was collected from the ninth century to the 19th, awaiting burial as required by Jewish law for anything bearing God's name.
Another of the artists whose work stands out is Torii Kiyonobu (1664-1729), the creator of "Erotic Contest of Flowers," which was given to the Boston museum in 1909 and has been kept in a storeroom of erotic material.
Manned by some of the most die-hard, gear-headed gentlemen you'll ever meet, the Hub comes with a storeroom of piled-up old bikes that they'll refurbish for you — and a greater social mission.
B2 ARTS E1-8 Bitdhas, byt BitBeforefore the Taliban blew up the giant Buddhas of Bamiyan last year, a squad of Islamic fundamentalists ransacked a storeroom of artwork from the National Museum in Kabul.
He kitted out a storeroom on the first floor of the NEMS store with a desk and typewriter.
The police were not able to immediately confirm a report by the local news media that an explosion in a storeroom on the top floor of the facility in Titisee-Neustadt in the Black Forest region had caused the fire.
Given this shortage, it might seem odd that one of the school's purpose-built classrooms has been emptied of pupils and turned into a storeroom for sacks of grain.
When I was in graduate school, my office was a desk in a basement storeroom of a natural history museum.
Then again, a storeroom full of animal bones was appropriate for an artist whose territory lies somewhere between the grotesques of Goya and the darker regions of Pee-wee's Playhouse.
