Certainly, all fabrics are "materials" and all materials can be use in whole or in part to make other things ....*as long as* the characteristics of the material work for the project it'll be used for.
A fleece blanket has characteristics like:
... won't ravel when cut
... usually made from synthetic fibers like polyester, etc, (rather than natural ones like cotton, linen, silk, etc)
...... because of that, the fabric won't breathe easily so sweat will be held in and air won't be able to circulate well
... easily machine washable and machine dryable
... thicker than most fabrics so a bit more difficult to sew (but still quite possible, either by hand or machine)
... can sew other fabrics to it, on it, etc, but many other fabrics will be different in texture, thickness, flexibility, etc.
... won't drape as well as thinner fabrics will
"Plush" fleece is the same basic thing, but the fibers are longer than regular fleece so will feel softer, and may have to treat it just a bit differently when sewing.