The transfer period is over, but there are still opportunities. There many good players without a club. Some names of them are big and i think that someone of them will still find a club.
Serge Aurier - Been very successful with Paris Saint-German.
Franck Ribéry - Everyone knows him
Marko Marin - 2019 Player of the year in Serbisch
Jack Wilshere - 182 games in the Premier League
Shkodran Mustafi - World Cup Winner 2014
Source:
https://www.transfermarkt.com/statistik/vertragslosespielerSerge Aurier is still a great right-back for most of the teams in Europe I believe. He is still only 28 years old and I think that it is still a young age for a back. He played in 27 matches in total at Tottenham in the last season. He got a performance with 2 goals and 3 assists. He was still very helpful for the team actually. But he is a free agent now. I heard that the Turkish team Fenerbahce are interested in signing him. Let's see where he will go.