Other members of the Board who were in place before that include Randal Quarles (Republican) since October 2017 and Lael Brainard (Democrat) since June 2014.
There were others who left before the completion of their 14-year terms, including Janet Yellen and Stanley Fischer. I believe either of these could have been the chair of the FED (Yellen as the incumbent chair, in fact).
Powell doesn't set FED policy on his own. There are five sitting Federal Reserve governors, and four of them were appointed by Trump. With two more nominees awaiting Senate confirmation, Trump will have appointed six of the seven Board members.
Are you really going to take the position that these people are all working to screw Trump? LOL.
Lael Brainard was not appointed by Trump, neither was Powell. Powell was an Obama apointee.
There are five on the board now, three were appointed by Trump.
https://en.wikipedia.org/wiki/Federal_Reserve_Board_of_Governors#cite_note-usc12-241-1