The January window can be a tricky one for Premier League and European clubs when it comes to transfer business.
However, there are still about eight free agents clubs could consider, even after the window shuts.
The 32-year-old re-signed for Atletico Madrid in 2017 but he and club agreed to terminate his contract last month.
The winger most recently played for Chinese club Jiangsu Suning, who he joined in 2016.
Now 34, the centre-back has been without a club since departing Valencia last summer.
Musa has been without a club since leaving Saudi Arabian club Al-Nassr in October and has been linked with West Brom in recent weeks.
A former team-mate of Costa’s, now 33, he last played with Brazilian outfit Palmeiras.
Bony has been without a club since parting ways with Al-Ittihad.
PSG terminated his contract in December but at 27, he still has time to rebuild his career elsewhere.
Niasse made a name for himself at Lokomotiv Moscow before joining Everton in 2016.
However, the Toffees who released the striker last summer after loan stints with Hull and Cardiff.