Manchester United secured the loan signing of Moroccan midfielder Sofyan Amrabat, while Turkish goalkeeper Altay Bayindir and left-back Sergio Reguilon also arrived at Old Trafford on Friday.
Amrabat, who starred in Morocco's run to the World Cup semi-finals last year, joins from Fiorentina for a reported 10 million euro ($11 million, £8.6 million) loan fee.
United then have an option to buy the 27-year-old for a further 25 million euros next year.
"I've had to be patient for this moment but I'm someone who always listens to my heart and now I am representing the club of my dreams," said Amrabat in a United statement.
"I am a passionate player; I want to bring that energy to the squad, and I will put everything into every action I take for the team."
Amrabat previously worked under United boss Erik ten Hag at Utrecht and brings some much-needed bite to the Red Devils' midfield.
"His committed, high-energy approach to the game fits perfectly with the group that we are building here," said United's football director John Murtough.
"We know that Sofyan's mentality, dynamism and technical qualities will help the squad as we look to achieve success in all competitions this season."
Bayindir joined in a deal worth a reported £4 million from Fenerbahce to back-up United's first-choice keeper Andre Onana, following Dean Henderson's move to Crystal Palace this week.
When Bayindir makes his United debut, he will become the first Turk to play for the club.
"It is a huge honour to join Manchester United and become the first Turkish player to represent this incredible club," Bayindir said.
"I have a passion for success, and I will give everything to help this special group of players to achieve our ambitions."
Bayindir's arrival completes a close-season of change in the United goalkeeping department.
David de Gea, who made 545 appearances in 12 years with United, left the club after failing to agree a new contract.
Onana joined from Inter Milan for £47 million, joining forces with Ten Hag, who also coached the Cameroonian at Ajax.
"Now we have the keeper group fully there," said Ten Hag. "I think we have a very good keeper group with the arrival of Altay."
Reguilon's arrival from Tottenham provides emergency cover at left-back with Luke Shaw and Tyrell Malacia both sidelined by injury.
The Spanish international joined Spurs from Real Madrid in 2020, but fell down the pecking order at Tottenham and spent last season on loan at Atletico Madrid.
"He's a very experienced player, played for big clubs, played already a lot of games in La Liga, Premier League, so, yes, I think very good background," said Ten Hag on Reguilon, who could be thrown in for his debut away to Arsenal on Sunday.
Centre-back Jonny Evans has also secured a one-year deal at United.
The Northern Irishman returned to Old Trafford, where he began his career, on a short-term deal earlier in the window.
"I am delighted to be back where it all began as part of this talented squad," said Evans.