UPDATE
According to Business Insider on 28 April 2017, in his first 100 days President Trump signed into law:
* a Senate bill on January 20, which allowed him to appoint General James Mattis as Secretary of Defense. Prior federal law prohibited individuals from becoming Secretary of Defense until they had been out of the armed forces for at least 7 years. Mattis retired from the Marine Corps in 2013
* H.R. 72 on January 31, authorizing the Government Accountability Office to obtain all federal agency records needed to perform its duties
* a congressional action in February, repealing a regulation which prevented coal-mining companies from dumping debris and toxic waste into nearby streams and waterways
* an action in February, abolishing federal standards that determined which schools were doing well in terms of students' performance and which ones were not
* a Congressional Review Act resolution in February, which rolled back financial disclosure requirements for energy companies mandated by Dodd-Frank Act. The stipulation required that energy companies disclose payments made to governments that related to fossil fuel development
* H.J.R. 40 on February 28, a bill repealing a rule which prohibited the mentally disabled from being able to purchase firearms
* H.R. 321 on February 28, the Inspiring the Next Space Pioneers, Innovators, Researchers, and Explorers (INSPIRE) Women Act. The law mandates that within 90 days of the law's passage, a plan must be submitted to the House Committee on Science, Space, and Technology for how NASA scientists can engage with and promote female STEM students from K-12
* H.R. 255 on February 28, called the Promoting Women In Entrepreneurship Act. The law authorizes the National Science Foundation to support entrepreneurial programs for women
* sH.R. 609 on March 13, a bill which designates a Department of Veterans Affairs healthcare center in Butler County, Pennsylvania the "Abie Abraham VA Clinic"
* Senate bill 442 on 21 March, which authorized the appropriation of funds towards NASA research and exploration
* a resolution on March 27, repealing a rule which prevented the government from working with contractors who had been in violation of labor laws, had engaged in wage theft, or were responsible for workplace safety violations in the last 3 years
* the Vietnam War Veterans Recognition Act of 2017 on 28 March, which designates March 29 as National Vietnam War Veterans Day and encourages the display of the American flag on that day
* a bill on 31 March, which designated a VA clinic in American Samoa to be named the Faleomavaega Eni Fa'aua'a Hunkin VA Clinic
* a Senate resolution in March, approving a memorial to recognize military men and women who had served in support of Operation Desert Storm and Operation Desert Shield. A joint resolution originally passed by US Congress before he became president
* a congressional review action in March, which abolished a land management rule aimed at streamlining the process for making federal land use decisions and giving ordinary people more input into federal land management decisions
* the repeal of a rule in March, which mandated that all states issue ratings for teacher-prep courses within their borders
* the abolition of a rule in March, which limited the number of unemployment applicants states could drug test
* a bill on 3 April, providing for the appointment of members to the Office of Compliance's Board of Directors in order to replace members whose terms were expiring in 2017
* a House resolution on 3 April, abolishing hunting restrictions on national wildlife refuges in Alaska. The rule was intended to protect predator species like wolves and bears from being hunted. The repealed rule also imposed a ban on aerial hunting, live-trapping or baiting predators, and from hunting those predators while they were near their dens or cubs
* a Congressional Review Act bill on 3 April. eliminating rules protecting private citizens' internet and browsing data from being used by their internet providers
* a measure on April 13, allowing states to withhold Title X family-planning funds from clinics which provide abortion services
* a bipartisan measure on 19 April, extending the duration of the Veterans Choice Program
* a House joint resolution in April, eliminating workplace safety regulations which were aimed at reducing injuries and deaths in the workplace
* a House resolution in April, eliminating a Labor Department rule regulating how large cities and municipalities design payroll deduction savings programs
* a bill in April authorizing a number of programs to enhance weather forecasting and alerts at the National Oceanic and Atmospheric Administration (NOAA)
* a Senate resolution in April which reappointed Steve Case as a citizen regent of the Board of Regents at the Smithsonian Institution. This was previously a joint resolution passed by Congress before Trump became president
* a measure which appointed Michael Govan as a citizen regent of the Board of Regents of the Smithsonian Institution
* a Senate resolution which appointed Roger W. Ferguson as a citizen regent of the Board of Regents of the Smithsonian Institution.