I have some light blue cropped Addidas trousers for the gym - come to about my knees, just under. And I have a couple of fitted (but not tight) sprts top - Nike ones I think. They fit nice and feel comfortable, without burying me!
Got mine from a standard sports shop though, not online.
i got my gym stuff from H&M in the sale ages ago!
some thinnish, cottony type cropped trousers and some jersey tops.
I hate wearing proper trackie bottoms because i get too hot! so go for the thinnest things I can find.