Well the prominent individualist anarchist and post-left writer Hakim Bey is a member of the IWW anarcho-syndicalist trade union.
He said this about joining the IWW:
"The Mackay Society, of which Mark & I are active members, is devoted to the anarchism of Max Stirner, Benj. Tucker & John Henry Mackay...As “individualists” moreover we have good reason to appreciate the IWW concept of the union. Stirner — contrary to the belief of those who have not actually read his book — spoke approvingly of a “Union of Unique Ones” (we prefer this translation to “Union of Egoists”), in which all members would reach for individual goals through common interests. He suggested that the workers had the most to gain by embracing this notion, & that if the productive class were to organize on such a basis it would prove irresistible. (The prejudice against Stirner, by the way, can be traced to Marx & Engels, who considered him potentially even more dangerous than Bakunin, & wrote their biggest book to destroy his influence.)...The Mackay Society, incidentally, represents a little-known current of individualist thought which never cut its ties with revolutionary labor. Dyer Lum, Ezra & Angela Haywood represent this school of thought; Jo Labadie, who wrote for Tucker’s Liberty, made himself a link between the american “plumb-line” anarchists, the “philosophical” individualists, & the syndicalist or communist branch of the movement; his influence reached the Mackay Society through his son, Laurance. Like the Italian Stirnerites (who influenced us through our late friend E. Arrigoni) we support all anti-authoritarian currents, despite their apparent contradictions."
"An esoteric interpretation of the I.W.W. preamble"