According to the Bill Clinton-era Congressional Review Act (CRA), Congress has 60 working days to review and disapprove new regulations issued by federal agencies. Thus any rule issued by the Obama administration since June 1 will be subject to the review by the new Congress in January. Congress can then disapprove any rules it dislikes and send them to the new president for his signature.
(Under the CRA, Senate filibusters are not allowed if the review is undertaken within 60 Congressional session days of rule issuance, so only a majority vote would be needed to reverse any so-issued regulation.)
Under President Obama, the CRA was useless because he would obviously never sign any disapproval legislation. President-elect Trump, however, has signaled his willingness to overturn his predecessor’s rules if he deems them burdensome or unnecessary.
Forbes magazine has compiled a list of 140 rules implemented since June 1 that will be subject to review by the incoming Congress: