Reading pair Sean Morrison and Jordan Obita have both signed new contracts at the Madejski Stadium.
Ipswich defender Aaron Cresswell has signed a two-year extension to his contract.
Millwall have confirmed they have begun talks to sign Oldham midfielder Chris Taylor.
Taylor has caught the eye of Lions manager Kenny Jackett, after several impressive displays for the Latics and his contract expires at Boundary Park this summer.
Meanwhile, the latest Millwall youth product to join the professional ranks is 18-year-old Jake Goodman, who put pen to paper on Monday.
The centre back, who grew up as a Lions fan watching the likes of Paul Robinson and Darren Ward, is relishing the prospect of playing for his boyhood club.
Goodman said: "I've got a lot to learn yet but I'm determined to work hard and hopefully if I keep improving I can force my way into the first-team squad.
"Robbo and Wardy have been great. They are excellent role models and I can learn a lot from them."