Arkam city map in arkam asylum
halo 2 scarab gun
super Mario bros in dying light games
My favorite easter egg still to this day is the Ghosts n Goblins music easter egg in Megaman 7.They way to find it for those who haven't found it is to hold down B button while choosing Shade Man from the stage select menu. I believe you can only do it on the SNES version but I may be wrong so you would have to find a SNES console and the game to do it.