Sidney/Sydney?
For me, Sidney for a boy obviously, and Sydney for a girl. If hearing them, without knowing spelling, I would assume girl.
Quinn?
I would always assume a boy. I have heard of a few girls called Quinn though, but I always thought it was masculine?
Parker?
For me, a boy name would be my preference, although obviously as unisex it can be both, but I know quite a few girls called Parker (nn Kerry).
Cameron (and Cameryn etc;)?
To me, Cameron is a boy name. I know a girl called Cameryn though.
Aubrey?
I didn't know it used to be a boy name!
Riley (Rylee, Rileigh etc;)?
I like it for a boy but know two girls called a variant of Riley. 
Kelly?
Dylan/Dillon?
Jordan (Jordyn)?
Taylor?
Cassidy?
Bailey?
Morgan?
Ashley?
Casey?
I know a girl called Casey and two boys, one called KC and one called Kasey.
Just wondering! Any other unisex names which you naturally assume to be one gender?