Unnamed Heroes

They are viewed as mere clean losses. They aren't even capable of warping out from the battle. They are expected to be spent by squadrons during battles. They draw bomber squadrons or assault boats so they will inflict overkill and spend their ammo in vain. They die so your Line Ships can live.
They are Escort Ships. In this case, Chaos Escorts.
Left: Infidel Class Raider. A torpedo boat, Infidel can cause mean damage even to line ships if taken in squadrons. They can also help to distract the fighters (from your bombers, for example) and become more effective as game progresses and enemy ships lose turrets. Infidel also carries four missile turrets.
Middle: Idolator Class Raider. Escort ship armed with a prow lance and four missile turrets. They provide a fire support against line ships.
Right: Iconoclast Class Destroyer. Smallest ship in Chaos fleet, Iconoclast is armed with six missile turrets and is good at fighting other escorts, but can also zerg rush line ships if squadroned or supported.