Possible Candidates To Beat Zoom
1. Wallace Rudolph West a.k.a Kid Flash
Before the season starts they had announced that Keiynan Lonsdale was cast as the Kid-Flash. Well the thing is, if Francine left when Iris was four and had a child within 9 months, that would make him between 19 and 21. Assuming of course that Barry and Iris are around 24-25 right now. Assuming he actually gets powers so he is old enough to beat Zoom with the help of Barry, Jay, and Dr.Wells by teaching him to use he's powers.
In the comics Kid-flash and Jay Garrick teamed up together to beat up Hunter Zolomon so we could see the two team up when Jay earn back his power.
2. Jay Garrick The Flash Of Earth 2
You may be thinking how in the world will Jay beat Zoom without his powers? Its simple he would recover from the damage he gained when he had fought Zoom when the breach opened. He could also beat Zoom with the help of Kid-flash.
We know that Jay lost his powers but how will he recover his powers back? We might see it in an another episode when both kid-flash and the flash was beaten by Zoom and their only last hope is to Jay recover back his powers and defeat Zoom temporarily.
3. The Green Arrow and Firestorm
Just like how they had beaten the Reverse Flash by teaming Arrow, Flash, Firestorm(Robbie Amell). With the new firestorm when they team up they could beat Zoom. Also with the help of Kid-Flash or Jay Garrick but its better when they all team up together for the Flash.