What is a typical monster? Usually it's a Orc blocking your path. After about 9000 Orc battles, though, the players might get a teeny weeny bit bored, you know. To add some flavour to your game, I'll present to you... the Top 5 anti typical monsters and characters!
4)A level 1 rat who has resistance to all forms of damage
5)An Epic Tier Fighter who drops dead immediately after taking a specific type of damage
However, there are roleplaying and realisticality factors to consider. Why would a Shardmind want to protect forests when his main goal is to rebuild the Diamond Gate(or whatever it was)? That doesn't mean you can't use these monsters and characters in your campaign, though. Maybe the Shardmind believes that only the power of nature can rebuild the Gate? Or maybe the Epic Tier Fighter got cursed to be incredibly weak to fire damage? Could it be the rat's ability to adapt to living in sewers that grants it high resistance? Or perhaps the Orc has realized that evil will never win? As you can see, a creative DM can provide realistic reasons for the anti typical monsters to be anti typical.