Paul Toner announced Tuesday that he is seeking a City Council seat, following up a run in 2017 when he was the final challenger eliminated in 19 rounds of ranked ballot counts.

The first City Council challenger new to the political scene has declared officially for the Nov. 2 municipal elections: data scientist Dana Bullister.

Three city councillors announced their intentions to run for reelection this week: first-termer Jivan Sobrinho-Wheeler on Wednesday, vice mayor Alanna Mallon on Thursday and Quinton Zondervan on Friday.

The upcoming City Council elections got their second announced challenger Tuesday in Nicola Williams, and the second coming from Cambridge’s small-business community.

Councillor Marc McGovern announced his reelection campaign Monday, asking voters to return him to office to continue work on priorities including affordable housing, homelessness, income and food insecurity, and climate change.

Theodora Skeadas, director of the small-business advocacy group Cambridge Local First, announced her candidacy for City Council on Friday with a list of priorities that is topped by economic challenges, followed by housing and racial justice issues.

Alanna Mallon is an incumbent elected in 2017 and seeking her second term in office.

Adriane Musgrave is a challenger with a background in business running for City Council for the second time.

Patty Nolan is a School Committee member running for City Council for the first time.

John Pitkin is a challenger with a background in demography running for City Council for the third time.