Former Hong Kong Monetary Authority chief
The 64-year-old, who stepped down as head of Hong Kong's de facto central bank in September after a decade, is seen as an apolitical bureaucrat favoured by the city's financial elite. While he helped steer the city through the global financial crisis, defended the currency's peg and managed property downturns, he also oversaw the city's finances during a period when affordability for first-time home buyers dived.
Former chief secretary
Mr Tang, 67, served as Hong Kong's No. 2 official through the global financial crisis and ran the city's finances for almost four years before that. His quest for the chief executive's role in 2012 failed after scandals, including an unapproved basement extension at his home to house an extensive wine collection. He denied any wrongdoing.
Mr Chan, 64, is currently spearheading economic policy in Mrs Lam's administration.
An accountant by training, he previously served as a member of the Legislative Council and secretary of development.
HK Executive Council Convener
Mr Chan, 54, has served as the convener of Mrs Lam's Cabinet since leading her election campaign in 2017.
He has worked with all of the city's chief executives since the former British colony's return to Chinese rule in 1997, and also served as a deputy to the National People's Congress, China's legislature.
Mr Cheung, 68, is Hong Kong's current No. 2 official and manages the city's affairs when Mrs Lam travels outside the city. He has worked in public service since the 1970s, including serving as the city's labour and welfare chief.
The 69-year-old is a member of the Legislative Council and Mrs Lam's advisory Executive Council who failed to get enough nominations to run for chief executive in 2017. She has been a public servant since 1975 and was the first woman to become secretary for security.