There´s a box of Dark Alliance Wargs for sale (HERE) without riders but they re the same ones which appear in the other sets, same poses and all have saddles and reins etc..and, the same Price as the ones with riders, which does seem a bit odd. Why buy the set without the riders?? Even if you only wanted the wargs so you could add different riders, Logic says, buy the set with riders and use the now "spare" riders for conversions.
Using that logic, I´d bought a second set of Wargs (Light) Dark Alliance (with riders) for possible conversions (draft animals for the Goblin slavers wagon for example) but then gave up on the idea of adding different riders.
Some riderless wargs seemed a good idea but with all the reins etc they look unfinished. Solution? Remove the saddles etc with a razorblade, then hide the cut marks by reproducing the fur effect with a heated pin. It doesn´t take Long, you don´t even have to be that carefull or accurate, the re-construction of the fur hides any leftover bits.