The number of people who have applied for mayoral nomination papers grew to 13 on Thursday, with Hassan Williams, who unsuccessfully challenged state Sen. Sonia Chang-Diaz in 2010, joining the pack.

According to the city’s Election Department, the rest of the individuals, who had applied for the papers a day earlier, are: Lee Buckley; pirate radio station owner Charles Clemons Jr.; William Dorcena of Hyde Park; former state Rep. Althea Garrison; John Laing Jr. of Hyde Park; Divo Rodrigues Monteiro of Dorchester; Barstool Sports’ David Portnoy; former City Councillor Gareth Saunders; Codman Square Health Center co-founder Bill Walczak; Christopher Womack of Hyde Park; David James Wyatt of Roxbury; and District 4 Councillor Charles Yancey.

Walczak, a Savin Hill resident, announced he was running for mayor earlier this month. His campaign manager will be Reuben Kantor, who has worked on the campaigns of Gov. Deval Patrick and City Councillor At-Large Ayanna Pressley. Kantor has also worked on Susan Passoni’s unsuccessful run for City Council in 2007, and for a year and a half, he was District 8 City Councillor Michael Ross’s chief of staff. (Ross has announced he is running for mayor as well.)

Yancey, the longtime city councillor, has also applied to pull nomination papers for his District 4 seat. Candidates are allowed to pull nomination papers for both the City Council and mayor, but they must gather separate signatures for both offices. (And if eventually elected to both offices, they must choose just one office to serve in.) Mayoral candidates need 3,000 certified signatures to get on the ballot.

Asked he was leaving City Hall if he has reached a decision, a coy Yancey said, “I have made a decision; I’m not going to tell you what that is.”

When Yancey, who was elected to the City Council in 1983, was told of a Herald report says he’s running for mayor, he appeared surprised. He was then asked whether it would be accurate to write he is running for mayor. Yancey said it would be inaccurate.

Tthe elected officials who’ve declared their intention to run for mayor have not yet applied for nomination papers. The first day candidates can apply was April 17, days after the Boston Marathon bombing and when most campaigns had suspended public activity. Papers can be pulled starting on April 30.

People who applied for City Council At-Large included Michael Bronner of Brighton; Christopher Conroy of Roxbury; Jerina Harris of Mattapan, who also applied for District 4 nomination papers; Francisco White of East Boston; and the South End’s Michelle Wu, a former campaign aide to U.S. Sen. Elizabeth Warren. Buckley and Saunders, who applied for mayoral nomination papers, also applied for City Council At-Large papers.