Buckler

In D&D v3.5 PnP, you can use a bow or crossbow without penalty while carrying a buckler. You can also use your shield arm to wield a weapon and you take a –1 penalty on attack rolls while doing so. In DDO, none of these are possible.

In DDO Bucklers may be chosen for a type of Swashbuckling by Bards. There is also an advantage for casters as bucklers have no associated arcane spell failure.