The formula that Barry writes on his board while he's trying to figure out how to be faster (3x2(9yz)4a) is the same formula that Johnny and Jesse Quick use to tap into the Speed Force in the DC comics.
At 18:30 Cisco refers to the Time Wraith as a Dementor, one of the evil dark wraiths in the Harry Potter universe.
According to Grant Gustin his favorite scene is, when 2016 Barry is captured and handcuffed, to the wheelchair by Harrison Wells (Eobard Thawne).
The idea of a Time Wraith appearing because of an incident involving time travel is very similar to the 2005 Doctor Who episode, Father's Day, in which Reapers appear because of a rip in time.
Cisco refers to the time wraith as "Inky", the name of one of the ghostly pursuers in the video game Pac-Man.