This is a well put together iconset, which is free by the way.  It is arranged nicely and is the most inclusive set I have encountered.  It would be difficult to find something lacking from this set if you are intending to make an rpg.  This is one of my favorite iconsets.

Only downside is that my developers on limited budgets are attracted to it, so if originality is paramount in your games, this would be a poor choice for that.