1. Battle of harpies against magogs and a stack of hydras in Lord Rings.
2. Imp against a dark knight in Ira the Mage.
3. Some battles in Bug-Race - troll vs cerberuses and nagas, manticores and archdevils vs black dragons.
4. Fake suicide in Ira the Mage.
+ a battle of a hobbit against harpies in RotSK, but you already know about that.
I could suggest some more battles from my first map, but spoiling it myself wouldn't be very fun! ))