Peek-a-Boo has had adventures outside of the traditional storyline in The Flash, as she was briefly highlighted in the official web series The Chronicles Of Cisco.
It’s highly doubtful, but still worth noting all the same, especially if she shows up in someone else’s subconscious.
One is the Syfy crime drama Hunters, and the other is the Hulu cult-ish drama The Path, and she was also in the feature AWOL.
Peek-a-Boo battled a pre-meta Cisco in a dream and shot him, although it didn’t exactly work, as Cisco inadvertently invented a bulletproof material using orange soda.