Aside from the big guns (bar BoJo,) May, Hammond, Green and Rudd, the Cabinet, like much of the UK establishment, was pro-EU during the referendum. Health Secretary Jeremy Hunt and Chief Secretary to the Treasury (previously Lord Chancellor) Liz Truss have both recently professed to having changed their minds on the big issue of the day, after voting to stay on the 23rd June 2016.
Gavin Williamson is also a big name to have switched 'camps,' though this is supposedly due to his private leadership ambitions and hopes to win over the Party faithful.
David Gauke, Greg Clarke and David Lidington were also pro-EU - as well as the recently 'disgraced' Michael Fallon, Secretary of State for Defence since 2014.
Theresa May has, whether purposefully or not, kept the Brexit influence from within her cabinet to a minimum. The obvious 'three Brexiteers,' Liam Fox, Boris Johnson and Michael Gove occupy important roles - namely International Trade, the Foreign Office, and Environment. Indeed, it is the outward facing roles which are predominantly occupied by pro-leavers - previously Priti Patel and now the popular Penny Mordaunt occupy the office of Secretary of State for International Development, and David Davis, a lifelong Brexiteer, fronts the negotiations with the EU.
The Conservative Party was the major Party with the biggest split during the referendum campaign period - with 185 backing Remain against 138 Leavers (from the Parliamentary Party at the time.) In comparison, only 10 Labour MPs backed leaving, and nobody from the SNP or Lib Dems did so. On the flipside, 100% of the Democratic Unionist Party, Theresa May's current bedfellows, were ardent Leavers.