A select number of distinguished Roman officers known as "Centurions" were so-named because they originally were in control of large legions of roughly 100 men. The historical Roman Centurion Armour Display comes complete with stand, Helm and Segmentata.
Gladiators typically did not wear a lot of armor, as it tended to make the fight more risky and therefore, more exciting. Many gladiators went into battle wearing minimal armor, including something like this Brass Gladiator Neck Guard.
The armor a gladiator wore often depended on their type, although a more common piece of gladiatorial armor was this Brass Gladiator Scaled Arm Guard. This protector offers the defense of metal armor in a rather lightweight package.
In Ancient Rome, members of the Praetorian Guard were often immediately recognizable. Not only was their position one of power, but they were a noble corps, wearing the finest armor, including pieces like these Brass Praetorian Greaves.