MythCraft is a Minecraft server plugin implementing various traditional classes, whilst aiming to keep commands to a minimum. It primarily aims to alter the way people play Minecraft, rather than adding command-powered skills. I do this by drawing inspiration from original minecraft features, such as undead burning in the sun, but also from traditional folklore such as the inhuman speed and thoughness of vampires. A primary goal of this plugin is to make sure the player isn't limited by the plugin, but "bent" towards different behaviour.
Be warned, this works for Minecraft 1.7 only and classes haven't been updated for newer versions.