Edith Creamer alleges that her father Robert LiButtie, a close associate of the late Gambino boss John Gotti, "had a longtime relationship with Donald Trump that included gambling millions of dollars at one of his casinos, flying on his helicopter and partying aboard his private yacht" as reported by Michael Isikoff for Yahoo News. Apparently, LiButtie was a tad racist, and at his request Trump Plaza in Atlantic City removed black dealers from crap tables at which he was playing: "investigators found that LiButti had, on multiple occasions, berated blacks and women using what one state official described as the 'vilest' language -- including racist slurs and references to women in obscene terms -- and that the Trump Plaza, in order not to lose his substantial business, sought to accommodate him by keeping the employees away from his betting tables." Of course, a racist streak is relatively common among wise guys.
Donald Trump long has been haunted by allegations of mob dealings as reported by Linda Qui for Politifact: "Trump's business dealings with the mob or mob-related characters are widely documented."
Among those whom Trump counted as his personal friends were self-loathing homosexual Roy Cohn and gay bar owner William Fugazy. The pair were bosom buddies long before their relationship with Trump. Fugazy and Cohn were promoters of the second and third Ingemar Johansson-Floyd Patterson heavyweight title fights in 1961 and 1962. Cohn client Genovese boss Anthony "Fat Tony" Salerno was suspected of providing the financial backing for the first fight in 1959 on behalf of other promoters. Fugazy was the one-time owner of Julius Bar who brought the 1966 lawsuit which successfully challenged the New York State Liquor Authority for its discriminatory policy against serving gay people.
Further reading that may be of interest: