WWE has brought back several wrestlers since the most recent brand extension, with some like Jinder Mahal receiving a far bigger push than ever before while others like Rhyno have mostly been lower card fodder.
With WWE planning to sign more male wrestlers in the fall after the Mae Young Classic, there has been internal discussion about which former wrestlers to reach out to about a return in addition to some of the younger talent the company is looking at that they've never signed before.
One top independent name that has caught WWE's attention is Sami Callihan, who departed the company in late 2015 after an uneventful run in NXT as Solomon Crowe. Callihan requested his release to prove himself in hopes that he would be back one day.
William Regal in particular has spoken highly of Callihan and he is on Triple H's radar as a hot act on the independents he wants to bring back at some point. It may be 2018 though by the time an offer is made as Triple H usually looks to restock the NXT cupboard with an existing independent name early in the year when he knows NXT is about to be raided by Raw and SmackDown after WrestleMania a couple of months later.
As noted, Adam Cole is on track to debut at NXT TakeOver: Brooklyn, while another former ROH star in Bobby Fish debuted at Friday's NXT tapings. As of this writing, it's unknown whether or not Fish has signed a contract or is just appearing on a per-basis, much like Samoa Joe, James Storm, and Eric Young did. Fish's tag team partner Kyle O'Reilly is also on WWE's radar.