The phrase "a tiny army of" is correct and usable in written English.
It can be used to describe a small group of people or things that are working together or acting in a coordinated manner, often in a context that emphasizes their collective strength or effort despite their small size.
Example: "In the garden, there was a tiny army of ants working tirelessly to transport food back to their colony."
Alternatives: "a small battalion of" or "a miniature force of".
A lavish party — designed by the government to court the Japanese industrialist Mr. Hosokawa, with a special performance by the internationally esteemed lyric soprano Roxane Coss, whom he has long loved from afar — is invaded by a tiny army of terrorists, consisting of three revolutionary "generals" and fifteen youthful recruits from the impoverished countryside.
(NB: The Slither poster looked like a tiny army of sundried tomatoes joining a girl in the bath).
So Kenya decided to extend her project beyond Instagram, making a tiny army of pocket-sized white men.
They have questioned how a poor orphan living on a tiny army stipend could donate so much money to the needy, and how he collected more than 300 pounds of cow dung on a single day during Chinese New Year.
A tiny army, the Maccabees, led a revolt.
He was second in line (behind his older brother) to the throne of the Kingdom of the Two Sicilies, a monarchy that was overthrown in 1860 by Garibaldi and his tiny army of Redshirts.
She might never find out where the infection was, but the antibiotics would shore up his tiny army of white cells and treat it.
Jack felt the booming resonance of the surf all the way down to his bones, and he stood very still and watched the sand release its dwellers, tiny armies of crabs rising out of the ground.
When would the Northern Alliance, forever "poised to take" Mazar-i-Sharif, actually move what looked like its couple of tanks and a tiny stage army of men?Western television-watchers were not alone in their doubts.
(Last spring alone, before leaving on a trip through southern Africa, he learned three hundred and fifty calls, including that of the blacksmith plover, which he likened to a "tiny little army of blacksmiths with tiny little anvils").
And if it had not been for Mr. Harold and a tiny guerrilla army of like-minded transit employees who bent the rules, disregarded orders and played hide-and-seek with subway cars sentenced to execution, many of the otherworldly old cars now sitting in the museum would have become just so much scrap metal, too.
