Former heavyweight champion Muhammad Ali and his third wife, Veronica, have filed for divorce. Ali, 43, and Veronica, 29, were married eight years . . .

Arizona Gov. Bruce Babbitt is another one of those Democrats being mentioned for 1988 and rumors began circulating he was looking for a house here. His press secretary Jim West explained yesterday that he is looking for a residence for his American Horizons Foundation and Americans for the National Interest, his political action group. West added, however, "the only house he's hunting is probably the White House" . . .

Dr. Dennis O'Leary, president of the D.C. Medical Society and the George Washington University hospital physician who's face became familiar as the official spokesman after the assassination attempt on President Reagan in 1981, may be about to change jobs. He is considered to be a principal contender for president of the Joint Commission on Accreditation of Hospitals in Chicago . . .

Radio/television talker Larry King, who doesn't need any more money, is signing a contract for an undisclosed sum with Putnam . King's agent, Sterling Lord, called with an offer no one could refuse: "How would you like to do a book where you don't have to do anything?" That question appealed to King and next year, "Tell It to King," a collection of the best King interviews over 25 years will be published . . .

Bidding continued yesterday on Sam (Pit Bull Terrier) Donaldson's book. The battle was down to three publishers, Random House, Simon & Schuster and Bantam, with a final contract offer expected sometime today . . .

In the what-a-shock department: The July Washingtonian magazine is the annual "best and worst" issue. In the list of best monthly magazines, The Washingtonian comes in first . . .

And adding to the sting of losing, the Gary Hart presidential campaign was sued in D.C. Superior Court yesterday for $7,083.32 cents for nonpayment of back rent and other costs for a campaign office on Eighth Street SE . . .

There can't be a better spot in Washington to have breakfast. The National Zoo, under the Friends of the National Zoo, is offering orange juice, coffee, doughnuts and bagels from 9 to 10 a.m. daily at the Panda Ice Cream Kiosk, located next to the Panda House . . .

It's probably a good lesson in "never say never." There was a party Tuesday night at the Georgetown home of Washington Post Executive Editor Ben Bradlee in honor of Newsweek political and national security correspondent John Lindsay, who has been ill. And then the telephone rang. It was former president Richard M. Nixon. Lindsay went to the phone and after talking a while, Nixon, realizing the significance of his call said: "Just remember, people said that Dick Nixon would never go to China, but I did. They said I'd never call Ben Bradlee, but I did." . . .