Ray Kelly
Kelly did two stints as New York City police commissioner, under Mayors David Dinkins and Michael Bloomberg. Kelly is highly respected in law enforcement and had a strong reputation with community leaders in New York. However, his involvement with the New York Police Department's controversial surveillance of mosques and Muslims in the years after the September 11, 2001, attacks could create resistance in Congress.
A bigger problem for Kelly could be his age: 75. That would make him 85 by the end of the 10-year term for FBI directors.
Mike Rogers
The former House Intelligence Committee chairman and seven-term congressman from Michigan has one obvious qualification: He's a former FBI special agent.
Rogers briefly served on Trump's transition team but was removed in a reshuffle in mid-November. Even the brief time Rogers spent aiding Trump will fuel questions about his independence. But a Benghazi probe he led as Intelligence Committee chairman essentially cleared Hillary Clinton of wrongdoing, which could reassure some Democrats.
Ken Wainstein
A longtime federal prosecutor now in private practice, Wainstein served as the first head of the Justice Department's national security division when it was formed in 2006. He previously was the U.S. attorney in the nation's capital under President George W. Bush. Wainstein also brings FBI experience, having served as general counsel and chief of staff to FBI Director Robert Mueller.
Wainstein, who is widely respected by prosecutors and law enforcement officials, was reportedly considered by President Barack Obama as a replacement for Mueller in 2011 before Obama asked Mueller to extend his term by two years.
Trey Gowdy
The former federal prosecutor and four-term GOP congressman from South Carolina is considered by his colleagues an authority on law enforcement matters. He may fit Trump's vision of an FBI chief, but Gowdy comes with significant baggage: His tenure as the head of the House Benghazi Committee, which focused intently on Hillary Clinton's role in that controversy and on her emails. That may cause Democrats to question Gowdy's independence from the White House.
In a statement Tuesday, Gowdy called for "an independent-minded" replacement for Comey.
Chuck Rosenberg
Rosenberg is a veteran federal prosecutor who is currently serving as acting chief of the Drug Enforcement Administration. Before taking that post, Rosenberg was chief of staff to Comey — a connection that might be too close for comfort for Trump.
Rosenberg is highly regarded by Republican and Democratic lawyers. He served in a series of high-level roles at the Justice Department and as a prosecutor in northern Virginia. Of potential interest to Trump: Rosenberg has experience with law enforcement at the Mexican border from a stint as acting U.S. attorney in southern Texas about a decade ago.
George Terwilliger
Terwilliger served as deputy attorney general under President George H.W. Bush in the early 1990s, after serving as U.S. attorney in Vermont and as a federal prosecutor in Washington.
Terwilliger spoke out against Comey's decision in October to disclose that the FBI had reopened the Clinton email probe to examine new evidence. "There’s a difference between being independent and flying solo," he told The New York Times.
Terwilliger has been active in Republican political circles and in 2014 called for a special counsel to investigate the IRS' targeting of conservative groups. In private practice for the past couple of decades, he's currently defending former Rep. Aaron Schock (R-Ill.).
Larry Thompson
A former deputy attorney general under President George W. Bush, Thompson joined with Democratic lawyer and former Deputy Attorney General Jamie Gorelick in a Washington Post op-ed last fall that blasted Comey for his decisions to publicize aspects of the Clinton email probe.
"We now have real-time, raw-take transparency taken to its illogical limit, a kind of reality TV of federal criminal investigation," they wrote. "It is antithetical to the interests of justice, putting a thumb on the scale of this election and damaging our democracy."
Thompson enjoys a strong reputation among former Justice officials, but at 71 his age could also be an issue. Trump could make history by nominating Thompson: He'd be the first African-American to head the FBI, which is struggling to improve the diversity of its special agent corps.
Mark Filip
Filip, also a former deputy attorney general under George W. Bush, has some résumé points other contenders lack. He was a federal judge in Chicago before taking the No. 2 job at DOJ. He also served as a law clerk to Justice Antonin Scalia, whom Trump is fond of praising.
Fran Townsend
Townsend is best known as homeland security adviser to George W. Bush, but she started her career as a federal prosecutor in New York City, serving for a time under then-U.S. Attorney Rudy Giuliani. She held a series of high Justice Department posts during the Clinton administration, including as an adviser to Attorney General Janet Reno.
Townsend was reportedly in the running for Homeland Security secretary, but Trump ultimately opted for Gen. John Kelly for that post.
Townsend would also give Trump a chance to make history by naming the first woman as director of the FBI, but some Republicans have long been wary of her because of the roles she filled at DOJ during the Clinton years.