Aaron Ramsey and Diego Godin have already signed for new clubs, while Ander Herrera and Mario Balotelli are among the big-name free agents.
Club Brugge forward Wesley is set to join Aston Villa, after the Premier League club confirmed they had agreed a deal for the 22-year-old.
Netherlands head coach Ronald Koeman has the inside track on Ajax captain Matthijs de Ligt's future but is keeping it to himself.
Emiliano Martinez, who has played only once for Arsenal this season, will spend the rest of the campaign with Championship side Reading.
Jose Antonio Reyes is back playing in Spain following a brief spell in China, joining Extremadura in their relegation battle.
Ashley Cole will play for Derby County for the remainder of the 2018-19 Championship season, reuniting with Frank Lampard.
Despite being linked with Manchester United in the previous transfer window, Harry Maguire is not expected to be on the move in January.
Petr Cech is not interested in speculation over his future at Arsenal despite being linked with a return to former club Chelsea.
Cristiano Ronaldo is reportedly nearing a move to Juventus and Gianluigi Buffon would not be surprised to see it completed.
Linked with a move from Real Madrid, Marco Asensio will remain at the Santiago Bernabeu, his agent said.