Here's the survey to end all surveys (well probably not) in which the Trump administration is asking the public which parts of government don't seem to be accomplishing anything beyond keeping bureaucrats employed.
Go here and work your way through the lists of departments and agencies, noting that there are 2 categories, elimination and reform. It may take a while as there are a LOT of departments and agencies, many of which you've probably never heard of. As a rule of thumb, if you have no idea what an agency actually does, and you can't puzzle out a useful function from its title, vote to dump it.
Remember that most regulatory departments are run by people friendly to the businesses being regulated and are run so as to make competition in that area more difficult. Protection for incumbents.