As I understand, these are the easter egg issues:
#077: World to End, or Possibly Just Mark Anniversary
#078: Easter Egg: Should We Pull The Lever?
#080: Easter Egg: Aliens Wish Peace/Trade Agreement
#215: Easter Egg: What's Your Favourite Colour?
#223: Easter Egg: Zombie Attack!
#256: Easter Egg: Suburbs Are Out Of This World
#266: Breaching the Great Fourth Wall of @@NAME@@
Green = Known
Yellow = Vague
Red = Unknown
Capital city, Leader and Religion issues
That's all I could find. If anyone knows anything, please add it.