Ed Martin, the government's pardon attorney, posted on social media a signed proclamation of the "full, complete, and unconditional" pardon of 77 people.
The list names Sidney Powell, a lawyer who promoted baseless conspiracy theories about a stolen election, and John Eastman, another lawyer who pushed a plan to keep Trump in power.
The proclamation, posted online late Sunday, explicitly says the pardon does not apply to Trump.
Trump's former chief of staff, Mark Meadows, is also on the list.
Presidential pardons apply only to federal crimes, and none of the Trump allies named were charged in federal cases over the 2020 election.
But the move underscores President Donald Trump's continued efforts to promote the idea that the 2020 election was stolen from him, even though courts around the country and US officials found no evidence of fraud that could have affected the outcome.
It follows the sweeping pardons of the hundreds of Trump supporters charged in the January 6, 2021, riot at the US Capitol, including those convicted of attacking law enforcement.
The proclamation described efforts to prosecute those accused of aiding Trump's efforts to cling to power as "a grave national injustice perpetrated on the American people".
It said the pardons were designed to continue "the process of national reconciliation".
"These great Americans were persecuted and put through hell by the Biden Administration for challenging an election, which is the cornerstone of democracy," White House press secretary Karoline Leavitt said in an emailed statement.
Those pardoned were not prosecuted by the Biden administration, however.
They were charged only by state prosecutors who operate separately from the Justice Department.
Also pardoned were Republicans who acted as fake electors for Trump in 2020 and were charged in state cases of submitting false certificates that confirmed they were legitimate electors despite Democrat Joe Biden's victory in those states.
Another key figure on the list is Jeffrey Clark, a former Justice Department official who championed Trump's efforts to challenge his election loss.
Trump himself was indicted on felony charges, accusing him of working to overturn his 2020 election defeat.
But the case brought by Justice Department special counsel Jack Smith was abandoned in November after Trump's victory over Democrat Kamala Harris because of the department's policy against prosecuting sitting presidents.
Giuliani, Meadows and others who were named in the proclamation had been charged by state prosecutors over the 2020 election, but the cases have hit a dead end or are just limping along.
A judge in September dismissed the Michigan case against 15 Republicans accused of attempting to falsely certify Trump as the winner of the election in that battleground state.
Giuliani, Powell, Eastman and Clark were alleged co-conspirators in the federal case brought against Trump but were never charged with federal crimes.
Giuliani, a former New York City mayor, was one of the most vocal supporters of Trump's unsubstantiated claims of large-scale voter fraud after the 2020 election.
He has since been disbarred in Washington, DC, and New York over his advocacy of Trump's bogus election claims and lost a $US148 million ($A226 million) defamation case brought by two former Georgia election workers whose lives were upended by conspiracy theories he pushed.
Eastman, a former dean of Chapman University Law School in Southern California, was a close adviser to Trump in the wake of the 2020 election and wrote a memo laying out steps Vice President Mike Pence could take to stop the counting of electoral votes while presiding over Congress's joint session on January 6 to keep Trump in office.
