Knockdown is a texture obtained by splattering drywall mud, then lightly pressing a spatula so it flattens, without spreading evenly through the surface. If patching a knockdown, it can be done with a few different Technics. There is no such “roller” that will give you a true knockdown.
Orange peel is a type of texture of a paint, just like eggshell is another. It is not a roller that will do it, but the proper paint you buy. If “orange peel” texture is what you want, then just go to a local paint store like Sherwin-Williams, Home Depot, Lowe’s… and explain what you want, and they will provide you the proper paint you need.