Realm is a tile where the colour will naturally become one of the strongest elements in the room. The deeper Blue, Garnet and Green shades can create an enveloping backdrop, while Amber and Red bring considerably more warmth. Pearl takes a quieter approach, allowing the variation in the glaze to provide the interest.
With a heavily varied tile, I'd resist trying to introduce another major pattern alongside it. That doesn't mean the rest of the room needs to be plain - timber, stone, aged metal and interesting cabinetry can all work beautifully - but giving the eye somewhere quieter to rest makes the glaze much more noticeable.
It's also worth looking at the less obvious tones within the tile. Realm's stronger colours aren't completely one-dimensional, so a surrounding material that picks up one of those secondary tones can often work better than an exact match to the dominant colour.