There were a variety of gladiator types, from the rare – like the scissor – to the very common, like the iconic retiarius. The list below is not exhaustive, but it lists the most common types, as well as some of the rarer fighters.
Andabata: a rare type of gladiator who fought blindfolded. On horseback. No one really knows how that worked, but one hopes the horses were well-trained. No images available that I know of.
Dimachaerus: a gladiator who fought with two swords rather than a sword and a shield. As we are very short on images of this type of fighter we are not sure what protective equipment they wore; this may have been a term for any gladiator who fought with two swords, no matter what type they normally were.
Essedarius: A gladiator who fought from a British style war chariot. This type may have been introduced by Julius Caesar after his ‘conquest’ of the island. We hear of a female essedarius in Petronius’ Satyricon (45).
Hoplomachus: A “shield-fighter” – the word is originally Greek. He carried a short round shield, a spear, and a dagger, deriving from Greek infantry equipment. He had a helmet and greaves as well. A pottery image of a hoplomachus (on the right) fighting a Thracian, can be seen here.
Murmillo: a heavily armed gladiator whose helmet had a decorative murmillo, a type of salt-water fish, on it. He had a large oblong shield behind which he crouched and used a gladius, a short thrusting sword. A tiny 1st century CE ivory figurine of a murmillo can be seen here.
Provocator: a heavily armed gladiator, who was also, unusually, protected by a breast-plate; this type was rather slow and clumsy and they were normally matched against each other.
Retiarius: a net fighter, perhaps the most iconic gladiator type of all. His weapon was a trident and he tried to trap opponents in his net. He had very little protective equipment and wore no helmet; Suetonius (Claudius 34.2) tells us that the emperor Claudius like to watch these die, because their lack of a helmet meant that he could watch their death agony better.
In this 2nd century CE mosaic from a Roman villa in Nennig, Germany, a retiarius strikes at a secutor. (Source: wikicommons)
Secutor: Literally “follower”, a type of gladiator usually matched against a retiarius. He was armed very much like a murmillo, but had a different helmet with very little visibility from two small eyeholes, which was designed so the retiarius net could not catch easily and the trident was better deflected.
Samnite: One of the original types of gladiators, named after an Italian tribe that was once an enemy of the Romans; when the Romans became friendly with them, this type vanished, to be replaced by the Thracian.
Thracian: A type of gladiator who fought with a small shield (called a parmula) and a curved, short sword. Spartacus fought as a Thracian; here’s a modern re-enactor dressed as a Thracian. For those who prefer the Starz version, go here. (Any actual historical truth in the last link is almost entirely accidental and dependent on it involving lack of clothing.)