Fancy Eggs only appeared in the episode Rule of Dumb and What Ever Happened to SpongeBob?. They are metal eggs decorated very fancily with gold, silver, and/or diamonds. Squidward has a collection of these eggs, he said so in What Ever Happened to SpongeBob?.
 Fancy Jewlery Egg
Mr. Krabs wants that Squidward, Sandy and Patrick look for SpongeBob. But Squidward doesn't want to so, Mr. Krabs gets a Jewlery Egg from his pocket and Squidward said that it's the last known jewlery egg that he doesn't have in his egg collection. They find SpongeBob and when he goes back out of the Krusty Krab and then Squidward slips on oil on a Spatula and the jewlery egg falls out of his hand and lands on SpongeBob and it gets destroyed.
On a Jewlery Egg you can see red jewlery and green diamonds. To Squidward it is a very special object.
 Fancy Egg Display
The Fancy Egg Display just appears in the Episode Rule of Dumb. In his house beside his swimming pool in Starfish form, "King Patrick" wanted to put a giant flat-screen TV on the wall or either over the fancy egg display.
Patrick: (slurping a drink and reading a magazine) I need your opinion on something. Do you think the giant flat-screen TV should go over the fancy egg display or the indoor swimming pool? (cut to Squidward sleeping then waking up to birds chirping and the sun shining)