Striker Vaughan missed the goalless midweek draw at Brighton due to a sore knee, while winger Bunn has been out since the middle of last month due to a hamstring injury.
Boss Chris Powell must decide whether to recall Vaughan to his starting XI or stick with Ishmael Miller up front alongside Nahki Wells.
Midfielder Jonathan Hogg is pushing for a recall and Powell will select from a full-strength squad as his side bid to extend their unbeaten run to five matches.
Derby will continue to assess leading scorer Chris Martin ahead of the trip to West Yorkshire.
Martin only recently returned to action after seven weeks out with a hamstring injury and the 20-goal striker missed the 4-0 home win against relegated Blackpool in midweek.
Asked if the Scotland international is likely to feature on Saturday, Rams head coach Steve McClaren said: “We don’t know. Chrissy might be fit again but he is not match fit. It is not just getting players back on the field, it is the level they have got to come back at.”
Will Hughes will be back in the reckoning after a two-match suspension but fellow central midfielder George Thorne (thigh) and defender Jake Buxton (back) are still out, although both players remain on course to return for the final Championship fixture of the season against Reading at the iPro Stadium on May 2.