When the season comes to a close every year, there's no need for a practice squad because, you know, the Bengals aren't practicing. And since the team is no longer restricted to a 53-man roster because, you know, their season is over, teams largely sign their practice squad players to offseason contracts.
According to Kevin Goheen with the Cincinnati Enquirer and a brief release on Bengals.com, the Bengals moved most of their practice squad to the offseason roster. Those transactions include running back (full back) James Develin, linebacker DeQuin Evans, wide receiver Vidal Hazelton, linebacker Micah Johnson, cornerback Rico Murray, offensive tackle Matthew O'Donnell and quarterback Zac Robinson.
Due to the process of elimination (aka, no other names known to have signed), tight end Chase Coffman was prominently not amongst the offseason roster signings. It's entirely possible that Coffman signs later since there's no real deadlines anymore. Also defensive tackle Swanson Miller and John Bowie didn't signed to the offseason roster.