Among the victims are six women killed in Miami-Dade County in the 1970s.
An FBI spokesman told CNN: "We are hoping that someone - family member, former neighbour, friend - might recognise the victim and provide that crucial clue in helping authorities make an identification". "We want to give these women their names back and their family some long awaited answers".
Samuel Little, 78, sparked investigations into cold cases in several USA states after he began confessing to the crimes last May.
Buchwald said the sketches helped investigators break three other cold cases across the country.
Little reportedly told officers that he was a good drawer and promised previous year to produce portraits of his victims.
Pearl Nelson, 38, left, is holding a photo of her mother victim Audrey Nelson, as she is hugged by Mary Louise Frias, whose Godmother, Guadalupe Apodaca Zambrano was also a victim of convicted serial killer Samuel Little as they are surrounded by family of his victims following Little's sentencing.
The Texas Rangers say Little to date has confessed to 90 homicides nationwide over the past four decades.
The 78-year-old former competitive boxer last year confessed to committing 90 killings in the U.S. since the 1970s.
An FBI spokesman says authorities so far have confirmed Little's role in nearly three dozen cases.
Little has confessed to killing 93 people over more than three decades, starting in 1970.
The FBI believes Little went after vulnerable women, often involved in drugs or prostitution.
Details of the list - including the suspected gender, race, age of the victims, as well as the locations the suspected murders occurred - are based on interviews with the killer, with all but one of the unmatched victims being women.
Now the Federal Bureau of Investigation has released the pictures in hopes some of the victims can be identified. He remembers where he was, and what vehicle he was driving.
Holland was trained in cold cases and visited Little where he eventually gained his trust, Ector County District Attorney Bobby Bland told CNN. "Jackson, Mississippi-one; Cincinnati, Ohio-one; Phoenix, Arizona-three; Las Vegas, Nevada-one", Palazzolo said.
Little is serving a life sentence in Texas after pleading guilty in December in Odessa to the 1994 strangulation of Denise Christie Brothers, whose body was found about a month after she disappeared.
Authorities were able to place Little passing through the area at the time of the killing, and in exchange for a deal which moved him to a different prison, Little agreed to talk to investigators where he confessed to the murders. Many more are pending confirmation and a number remain uncorroborated.
He was arrested in 2012 in a homeless shelter wanted on drug charges in California.