The weapons allegedly included a Nerf football stuffed with nails, a device designed to hang from the ceiling and rain down ball bearings, a sniper rifle, machine gun, silencers and pistols, the New York Post reported Monday.
Ivaylo Ivanov, 37, was indicted on more than 100 counts of weapons charges and allegedly also drew swastikas and anti-Semitic statements on local synagogues.
Police said they don't know how Ivanov, who is Jewish, was planning to use the weaponry.
Police Commissioner Ray Kelly said investigators are poring over "voluminous" material seized from Ivanov's computer trying to find what he planned to do with the weaponry.
He could be sentenced to 25 years in prison if convicted on all charges.
Kate Middleton recycles dress at movie premiere
Beyonce flaunts bikini body, Blue Ivy in vacation pics