After multiple episodes of The Walking Dead kept Daryl out of commission behind bars in the Saviors' heavily guarded hideout, he finally made his escape in "Hearts Still Beating." But despite his past ingenuity when it came to getting out of sticky situations, Daryl didn't free himself from the Sanctuary. He had help in the form of a mysterious benefactor who left him a note and a key, but didn't leave behind a name. Daryl still had to find his way out of the maze-like building on his own, but someone did have to give him that first helpful nudge. So who helped Daryl escape on The Walking Dead? The way I see it is there are a few possibilities.
The most obvious would be Carl or Jesus because they were the only two of Daryl's known allies to appear at the Sanctuary while he was there. However, Carl was never let out of Negan's sight during his visit and Jesus seemed surprised to come across Daryl outside the building. That means that the person who helped Daryl had to be a Savior, because the Saviors were the only other people present. It's unlikely that Daryl's helper is a character viewers haven't met (because what would the point of that be?), so chances are it was one of the more sympathetic Saviors: Sherry or Dwight.
Very few of the Saviors have names or even clear identities, and a lot of them simply function as Negan's victims or his guard dogs. Both Sherry and Dwight have complicated histories with Negan and both of them don't seem entirely thrilled with how things are going at the Sanctuary. They're the two best options when it comes to figuring out who sprung Daryl, but they're imperfect options at best.
Dwight may hate Negan, but he's also been more than happy to take out his frustrations on Daryl. He stole Daryl's jacket and his motorcycle, plus he was never too friendly when hauling Daryl around the Sanctuary. Sherry was kinder to Daryl, but she also discouraged him from leaving during his first escape attempt, telling him that there was no chance of success and just trying to leave would only make things worse. If Dwight hated Daryl, why would he help him? And if Sherry thought things were hopeless, why would she help?
Considering Dwight defected from the Saviors in the comics, it seems very possible that he had a change of heart and decided to let Daryl go. Dwight was there when the Saviors looted Alexandria, so he knew how badly they all wanted Daryl back. Releasing Daryl would go a long way towards getting on Rick's good side, which would help Dwight a lot if he really did want to change sides and end Negan's reign of terror.