The next name to surface should be Chris Shula from the Rams, Todd Monken from the Rats or Joe Brady from Buffalo. Hell, I'd even flirt with Zach Orr from Baltimore, too.
OCs
-Klint Kubiak (OC Seattle) - Mixed results as an OC, but has been with three different teams. He's coaching under one of the better young defensive-minded head coaches right now, so you assume he has control over the offense. Kept Sam Darnold's success from Minnesota going and has one of the best offenses in the league and helped turn JSN into a superstar this year.
-Klay Kubiak (OC SF) - Lacks experience and Kyle Shanahan still runs the show, but he has a heck of a system that has the 49ers performing even with key injuries.
-Mike LaFelur (OC LAR) and Nate Scheelhaase (pass game coordinator LAR) - I'm interested in any offensive-minded coach under the McVay coaching tree. Zac Taylor, Matt LaFleur, Kevin O'Connell. McVay is arguably the best coach in the league and the Rams just had one of the more impressive rebuilds since their last Super Bowl. I think this would really modernize the Steelers approach on offense.
DCs
-Chris Shula (DC LAR) - He's helped build a strong defense with the Rams, including young draft picks performing well early on. His NFL pedigree certainly doesn't hurt.
-Kelvin Sheppard (DC Detroit) - Young DC, though lacks experience as a coordinator. He's done pretty well in his first year on the job.
College
-Marcus Freeman - I think he has the type of demeanor and style to translate from the college game to the NFL. He's recruited a lot of former Steelers' sons to play there, so they are impressed what what he is doing. He's been to a CFP title game and is a face-of-the-franchise type coach.
2nd-Time HCs
-*Sean McDermott - Big *if* is if he gets fired. Classic good coach who can't reach the big game, but he's had Tom Brady and Patrick Mahomes in his way. In 8 full seasons, he's had 6 10+ win seasons and has won a playoff game in 5 of 7 appearances. He's a good coach who could have learned through playoff failures.