Another gaming instructor of mine always encouraged the notion that any sort of art portfolio you have should be varied.
He stressed that having a consistent personal style is a good thing to have, as it gives your art identity. But still he stressed the importance of, as an artist, one being able to expand their abilities and exploring familiar and unfamiliar artistic territories. That way, you’ll be able to show potential contractors/employers that you’re capable of working with various styles, techniques, and mediums and are adaptable within your own artistic identity.
I think about this a lot, and it’s something I really need to keep working on myself.