Ron Rivera has prior Pittsburgh connection the last time they hired a head coach
Back when Bill Cowher decided to leave the game of football and left the Steeler's top coaching job up for grabs, there was an extensive search for his successor. Mike Tomlin ended up getting the job, but Ron Rivera was under consideration. He would have likely gotten another interview if the Chicago Bears did not play in the Super Bowl that year.
Rivera has done a respectable job as a head coach in the NFL between his time with the Panthers and now the Washington Commanders. Things have not gone great in Washington, but he has been able to get them to the playoffs without substantial quarterback play. Rivera is a defensive-minded coach that the black and gold would be familiar with from last time.
Hines Ward might be a long shot for Pittsburgh but it could make sense
Right now, it is unknown if Hines Ward will return for another season with the San Antonio Brahmas as the XFL is merging with the USFL for a spring football league. He was their head coach last year and the Steelers signed their best defensive player Luq Barcoo. Ward is one of the favorite players in the history of the franchise, and he has a good amount of coaching experience now.
He has grown his coaching resume, but the issue is that he has no substantial NFL experience on there. Other than being an intern and assistant, he has gotten other experience in college and the XFL. That will surely put a hindrance on his potential head coaching submission to the Steelers, but he would be an interesting choice that would fly under the radar.