Grey merino sweatshirt fabric- try Judge Grey, Koala grey or a merino interlock blend.

Black merino and lycra fabrics- Last pieces now listed for Bauer Black, Black Ink and Nero Black

A blend of merino with a small amount of lycra gives the fabric good one way stretch and some stretch the other way too. This means the fabric can be more form fitting to make figure hugging t shirts, tops, camisoles and leggings. 

The black merino and lycra blends are in several weights but nearly are sold out so have a look at the last pieces of Bauer Black, Nero Black and Black Ink if you want a stretchier fabric.