Derby shoes (also called bluchers in some American usage) have open lacing. That is the definition. Everything else — broguing, plain toe, colour — is variation.
They are the default recommendation for someone who wants one pair of leather shoes for work-casual and weekends. The open lace adapts to the foot better than a tight oxford. At YoyooBlue they are British-inspired casual derbies, often with visible stitching.
Browse leather derby shoes.