It depends on when and where you're talking about. The Arab is more or less unchanged.

The dressier of knight and armour fame is gone. They did provide input into modern heavy horses, especially the Percheron.

Germany developed a horse known as the Trakaener. It was and is a general farm horse in peacetime but with the weight, height, speed and endurance to be draftable as a cavalry horse (versus a logistics type draft horse ).

It's quite popular on the show horse circuit.