Hull have 10 players set to be out of contract in the summer - the most of any Yorkshire Championship club - although they do have an option in their favour to extend five players' deals by a further year.
Two of the Tigers' out-of-contract men have the option to extend their own contracts before their deals expire at the end of June.
Barnsley have three players coming to the end of their contracts, including left-back Ben Williams who has been linked with a permanent move to Cheltenham Town.
Chris Wilder's Middlesbrough have four players out of contract in 2022, with three seeing their current deals lasting until the summer while defender Neil Taylor is only contracted to the club until the middle of this month.
Boro are reportedly ready to hold talks with Taylor over his future at the Riverside Stadium with a number of Championship clubs reported to be interested in his services.
Below, is every Barnsley, Hull City and Middlesbrough player in the final year of their contract according to transfermarkt.co.uk.
1. Romal Palmer
Romal Palmer (Barnsley) - The 23-year-old joined the Tykes in the summer of 2020 and has made 20 appearances in the Championship this season. Photo: Getty Images
2. Aapo Halme
Aapo Halme (Barnsley) - The defender has been out with injury since the end of September. His current deal runs out this summer but he does have the option of a further year in his favour. Photo: Getty Images
3. Ben Williams
Ben Williams (Barnsley) - The left-back is currently linked with a move to Cheltenham Town with his contract set to end this summer. He joined Barnsley in 2017 but has not played since October. Photo: Getty Images
4. Jonny Howson
Jonny Howson (Middlesbrough) - The midfielder has played over 200 times for Middlesbrough and has continued to feature regularly this season. Photo: Getty Images