There was a stat at one point that rated Dier as one of the fastest in the league--believe it or not.
I don't know who records these things or how it's done. There are some lists based on highest speed reached; others look at certain distances covered in a certain time. Strikers/wingers need to be able to sustain speed over a long distance - half the length of the pitch or more - whereas defenders and midfielder benefit most from short bursts of acceleration over shorter distances to track back effectively or find space. Vardy, Martial, Mane & Walker seem to consistently come out on top as speed merchants over longer distances, but in terms of top speed reached, it might be surprising to learn that Koscielny, Pogba, Lukaku & Kante are in this season's top 10.