I found a reference to druids! In character creation in Arena, this message appears when you choose Breton as your race: http://i142.photobucket.com/albums/r105/Enoil/a_000.png
"Thy race [Breton] is descended from the ancient druids of Galen, quick witted and strong in the mystic arts."
Though this is obviously D&D related, it could be explained by present lore that this reference is to the Tribes of Manmeri found in the Reach by the Skyrim Expedition of Khosey, who were by that time already gifted with the talents for the 'mmystic arts', also even in present times, there is refernce to 'druid-like' goings-on in High Rock. E.g. in PGE First Edition, I quote "
In more remote regions, such as Glenpoint and the Wrothgarian Mountains, witches and medicine men, barely distinguishable from Orcish shamans, hold sway over the superstitious peasants with feats of untutored, but often impressive, magical ability. " which clearly could viewed as modern Druidism, also another quote from the PGE First Edition "
Reach-magic is still widely studied, although it is banned by the Mages Guild (who fear it as dangerous and wild hedge-wizardry), and the Reachmen are often referred to as the 'Witchmen of High Rock.'", another posible link to Druids, or atleast Druid-Like people living in the remote wilderness of Highrock.