The latest group of playable classes has been revealed in the Camelot Unchained version of Bards. Each realm has their own form of this support class that can both provide buffs and debuffs as well as other magical and musical combat touches.
As an example, the Arthurian form is the Minstrel:
It is said that members of this class will share a song from deep in their hearts to all in their Realm, while those from other Realms get a lute to the head! Minstrels use the power of song to aid fellow Arthurians in their travels, making the miles fall away faster and stiffening their spines during battle. The earliest Minstrels were known to wander the Realm, recording the hardships and triumphs, successes and failures, of all. Their songs spread stories of heroism among their fellow survivors, as well as stories of King Arthur himself.
Head to the Camelot Unchained site and read more about the Minstel and the Skald and the Dark Fool as well.