A nest of dragon eggs in Ultima VI
Dragon egg in Ascension
The simple truth of what dragon eggs are should be warning enough to not mess around with them, as the average adult dragon will not take kindly to any potential threat to its offspring.
In Ultima VI, the Avatar had to get a dragon egg from the dungeon Destard, before Sandy in Trinsic would reveal the remaining Ten Pirates of Hawkins to the Avatar. Any surplus eggs were given to Shubin at Serpent's Hold, who wanted to turn them into a special meal.
Dragon eggs were again seen in Destard in Ultima IX. However, by then they were so big that the Avatar couldn't carry them, managing only to acquire some cracked pieces of their shells.