Speed is more impressive at lower levels, and in the regular season v the playoffs.
The "smaller" the ice, the less speed matters.
But quickness and agility may be more important, both feet and hands, because more play is happening in a short area.
Then again, maybe not? Some surprising names on the following list, especially 400 or more minutes, which is unlikely to be a one playoff series fluke.
Top 5x5 pp/60 playoff scorers since 2008 (200+ minutes, bold is 400+, * is 800+):
Guentzel 3.40
Pastrnak 3,33
Briere 2.81
Downie 2.74
Leino 2.68
MacKinnon 2.67
Bergenheim 2.61
Benn 2.59
Umberger 2.52
Horton 2.52
Crosby 2.51*
Fabbri 2.46
T Johnson 2.45*
R Smith 2.42
R Bourque 2.40
Ryder 2.37
Jokinen 2.36
Kucherov 2.32*
Marchessault 2.28
Purcell 2.25
Point 2.24
Kane 2.23*
Savard 2.22
Prospal 2.19
Krejci 2.19*
Guerin 2.16
Larose 2.15
Franzen 2.14*
Marchand 2.13*
Doan 2.12
Satan 2.12
Malkin 2.10*
Radulov 2.10
Kessel 2.09*
Carcillo 2.08
Asham 2.07
Wolski 2.05
Landeskog 2.05
Haula 2.05
Matthews 2.04
J Williams 2.04*
Ward 2.04*
Lecavelier 2.02
Bergeron 2.02*