Fourteen have been named so far.
Michelle Kiss was described as “a loving wife to Tony, mother to Dylan, Elliot and Millie, as well as daughter to Mick and Christine and sister to Nichola”.
In a statement, her family said: “Family was her life and we are all obviously devastated by her loss.
“She has been taken away from us, and all that love her, in the most traumatic way imaginable.”
Sorrell Leczkowski, from Leeds, is believed to have gone to the Manchester Arena with her family to pick up her sister.
The 14-year-old Allerton High School pupil was killed and her mother and grandmother, who is critically ill, are in hospital.
Her sister, who was at the concert, was not injured.
A female off-duty officer from Cheshire Police was killed while at the concert with her family, Greater Manchester police has confirmed.
She was with her husband, who remains critically ill, and two children, who were injured.
Greater Manchester chief constable Ian Hopkins, who did not name her, said: “Very sadly I can confirm one of the victims is a serving police officer.”
School pupil Nell Jones, 14, from Cheshire, died in the attack, Holmes Chapel Comprehensive School has said.
“It feels like they have lost a sister not a classmate.”
Alison Howe and Lisa Lees
Friends Alison Howe, 45, from Royton, and Lisa Lees, 47, from Oldham near Manchester, were killed while waiting in the foyer to pick up their daughters.
The girls, both aged 15, are believed to be safe.
Ms Howe’s stepson Jordan Howe confirmed her death on Facebook, writing: “They took a caring beautiful mum and step mother away from us all she was amazing to us all.”
Jane Tweddle-Taylor, 51, from Blackpool, was killed in the foyer as she went to the Arena with a friend to pick up the friend’s daughter.
Her husband Mark said: “She’s a lovely lady and a very good mother to her three daughters. She was liked by everybody, especially in the community in Blackpool where she worked.”
She was a receptionist at South Shore Academy School in Blackpool and was a “bubbly, kind, welcoming, funny, generous” colleague, the school’s principal has said.
Jane Bailey described Miss Tweddle-Taylor as a “well-loved member of staff” and “wonderful friend and colleague”.
Angelika and Marcin Klis
Marcin and Angelika Klis, who were both from Poland and lived in York, were killed while collecting their daughters from the venue.
The Polish Foreign Minister Witold Waszczykowski told a radio station: “The parents came after the concert to collect their daughters and unfortunately we have information that they are dead. The children are safe.”
The Polish foreign ministry said: “We share the pain of the family and the loved ones of the victims and express our most sincere condolences.”
PR manager Martyn Hett, 29, was at the concert with his friend Stuart Aspinall when the pair became separated.
His former partner Russell Hayward said on Twitter: “We got the news last night that our wonderful iconic and beautiful Martyn didn’t survive.
“He left this world exactly how he lived, centre of attention.”
Kelly Brewster, 32, from Sheffield, died while shielding her niece from the blast, her family said.
Her uncle, Paul Dryhurst, said Ms Brewster had “heroically shielded” her 11-year-old niece from the explosion in the foyer after becoming separated from her sister at the end of the performance.
“Kelly Brewster wasn’t one of the unidentified hospital patients. She has sadly passed away in the terror attack.”
He added: “Kelly really was the happiest she has ever been and we had so many things planned together. My daughter Phoebe will be absolutely devastated like we all are.”
John Atkinson, 28, was described by friends as “a true gentleman” in online tributes.
Friends of Mr Atkinson, who lived in Radcliffe in Bury, have also set up a fundraising page to help his family, which has raised more than £4,000.
“A true gentleman. R.I.P John thoughts and prayers with you family and all of the other victims effected by this tragedy,” she said.
“John was one in a million and loved by so many,” she added.
Student Georgina Callander, thought to have been 18, had already met the US singer Grande before seeing her perform on Monday.
Before the concert, Miss Callander had sent a Twitter message to Grande, saying: “SO EXCITED TO SEE YOU TOMORROW”.
Olivia Campbell, 15, was a “precious, gorgeous girl”, her mother has said in an online tribute.
Charlotte Campbell, from Bury in Greater Manchester, wrote: “RIP my darling precious gorgeous girl… taken far far too soon go sing with the angels and keep smiling mummy loves you so much.”
She was a pupil at Tottington High School, where head teacher Brian Duffy described her as “a delightful young girl”.
Eight-year-old Saffie Roussos was “simply a beautiful little girl in every sense of the word,” said Chris Upton, head teacher at Lancashire’s Tarleton Community Primary School.
“She was loved by everyone and her warmth and kindness will be remembered fondly,” he said.
“The thought that anyone could go out to a concert and not come home is heartbreaking.
“Our focus is now on helping pupils and staff cope with this shocking news and we have called in specialist support from Lancashire County Council to help us do that.”