In the latest episode, we saw a female speedster named “Trajectory” wreaking havoc in the Central city after she stole the research of Prof. Harrison Wells and Caitlyn to develop a speed serum called “Velocity 9” which increases your speed force temporarily but with major side-effects. It is quite possible that Caitlyn finds a way to stabilize it and prevent cellular degeneration.
In DC Comic world Velocity 9 was developed by Vandal Savage. He formed a partnership with mobster Nick Bassaglia to use his heroin distribution network to make it available to stockbrokers & lawyers and gain control of the wall-street, their plans were foiled by the Flash but he lost his powers after he was injected with a drug.
Here is a list of people who may take Velocity 9 in the future in Flash Season 2:
The Earth-1 version of Wally West is supposed to become Kid Flash at some point in time. It is quite possible that he gets his powers from the Velocity 9 formula.
Barry Allen/ Flash:
When he came to know about the existence of Velocity-9, he was tempted to inject himself and increase his speed-force. Who knows if he faces Zoom next time and push come to shove, he may inject himself to defeat him.
He is a doting father who can go to extreme lengths to protect his daughter. He may inject himself with Velocity 9 and save his daughter from an external threat, he just gave sizeable quantities of his blood to Jesse to save her from the side-effects of Velocity 9.
It is very much possible that Jesse may end up consuming velocity-9, and that’s how she becomes a speedster.
The show-makers teased it in the beginning that it’s possible that Barry’s girlfriend may become a speedster for a brief period, it’s least likely that she may get her hands on the serum.