The hoverboard girl, known as Starlene in Ratchet & Clank (PS4), was a woman who advertised and hosted the hoverboard races in Blackwater City, planet Rilgar. She presented the Platinum Zoomerator to Ratchet after he won the annual competition. Starlene also appeared in Qwark's infobot for planet Umbris. In the aforementioned infobot, he was seen carrying her to safety; she was described as the "damsel in distress."
Behind the scenes
As an Easter egg (or potentially an oversight from the developers), if Ratchet kept sideflipping near Starlene, her breasts would grow much larger.