1. Trevor Siemian
The Bengals didn't re-sign Brandon Allen this offseason and opted to bring in Trevor Siemian instead. The former seventh-round pick out of Northwestern has bounced around the league but has experience as a starter, having started 30 games in his career.
After playing for the Bears in 2022, Siemian signed with the Bengals this offseason and ended up losing the QB2 battle to Browning. He didn't look good in the preseason but the one advantage he has over the other two guys listed here is that he at least knows the Bengals offense (or should anyway).
Siemian didn't sign with anyone after the Bengals went with Browning over him so he'd be available to bring back. He still likely sits behind Browning if the Bengals did opt to bring him back but at least he's somewhat familiar with the playbook and these Bengals players. That's something that McCoy and Wentz can't say.
The Cincinnati Bengals are not going to be the same team without Joe Burrow at quarterback. None of these guys are going to excite the fan base but they'd provide veteran presences to help out Browning and the rest of the team while Burrow is healing.