Usually it helps, in The Championship to have experience with relegation and how to deal with it. Off the top of my head I can think of:
Kelvin - Relegated with us previously plus relegated with Sunderland.
Bertrand was out on loan here, there and everywhere, it's likely he was part of at least one relegation but not sure.
Stephens would have been at Plymouth when they were relegated down to League One I'd imagine, even if it was as a 14 year old.
Redmond at Norwich and Birmingham.
Austin at QPR (possibly other places)
Anyone else? Not sure if Hughes was ever relegated as a player, he was before my time in that respect.