Derby County have released experienced trio Darren Bent, Chris Baird and Jason Shackell - but striker Chris Martin could have a future at the club.
Ex-England striker Bent, 34 - who joined Burton on loan in January - did not appear for the Rams all season.
Shackell, also 34, played just twice in the League Cup in 2017-18 and was loaned to Championship rivals Millwall.
Northern Ireland full-back Baird, 36, played 23 times but is also leaving the losing play-off semi-finalists.
Sam Winnall and Kasey Palmer will return to parent clubs Sheffield Wednesday and Chelsea respectively, after their loan spells ended.
But six players loaned out by the Rams including Scotland striker Martin, who finished the campaign with Reading, have all returned to the club and are still under contract.
The others are Craig Bryson, Jacob Butterfield, Nick Blackman and youngsters Max Lowe and Mason Bennett.
Derby Under-23s trio Joe Bateman, Lewis Walker and Matt Yates have all signed new one-year extensions.
However, fellow youngsters Alex Cover, Emil Riis Jakobsen, Kyron Stabana, Matthew Taylor and Ayomide Jibodu have been released.