If you're talking about textures as items, well they remained locked on that acc until your ban expires or idk if the ban is permanent the admins will eventually take those items.
If we are talking about textures as art, you basicly still own that art, but you can't sell it on your main as long as your ban exists or in the case of a perma ban you can't at all. I guess in the case of a perma ban you can ask a friend who plays the game to sell it in the name of you and you get the money from him, note do this only with people you trust if there's ever a case of this.