List all the easter eggs you know about.

-The name "Spielburg" means "Game city" or "Game castle." It's also reference to the director who did E.T. I believe the Coles chose the name "Spielburg" for both of these reasons.
-In the Spielburg Adventurer's Guild, there is an Antwerp that was slain by Two Guys from Andromeda. Admittedly I'm probably the only person who did not get that reference immediately. I played all the QFG games before I played the Space Quest games
-At the lake in Spielburg, you can sometimes see a periscope. Supposedly this is a reference to a Jim Walls game that's not "Police Quest" (I forget the name)
-You can also sometimes see the Loch Ness Monster at the lake.
-Erasmus's place has the Rosella Stone.
-Erasmus's place also has the knight from the first Laura Bow game.
-One of the "Quest For Glory" games has a "Daven Tree" (the first one or the 3rd one)
-Baba Yaga is a reference to Slavic folktales or something like that. She is not a creation of the Coles
-In the original QFG2, you can sometimes see a dead man in the desert. Apparently this is a reference to "Conquests of Camelot."
-In the QFG2 remake, you can sometimes see King Graham dead in the desert. I don't think this was in the original game because I think the original QFG2 came out before KQ5.
-Sometimes, when you are walking through the desert or through the Savannah/Jungle in QFG2 or QFG3, you can see some interesting signs on the ground.
-There is a Rosella doll in Keapon Laffin's shop.
-There are Antwerps in Keapon Laffin's shop
-Keapon Laffin's name is meant to sound like "Keep on Laughing"
-The food merchants at the fountain plaza in Shapeir are supposed to be Lori and Corey inserting themselves into the game.
-In WIT, Erana is meant to look like Genesta, and the game says that the hero once met Genesta. I actally noticed that Erana looked like Genesta even before I read about it. Of course Erana's appearance varies in games with differen't graphics, and we never see Genesta in any VGA game, so I don't know if the similarity has remained consistent.
-Raseir is an anagram for Sierra. I don't know what Shapeir is an anagram of or how it got its name.
-You can use the glasses from Keapon Laffin's shop to see Zayishah naked. You could do a similar thing in the first Laura Bow game, but that didn't give you full nudity so the Coles one-upped Roberta in that regard
-Iblis is also a reference to old folklore. He is not a creation of the Coles
-Ad Avis's name is a reference to Bill Davis, a Sierra employee who worked on many of their games.
-The weapon shop in QFG3 has a Lara Bow and a Dagger of Amon Ra
-Mordavia means "Dark valley"
-Dr. Cranium is meant to be related to Dr. Brain, another character created by the Coles in a very different style of game
-If you look at the fairies who try to take your staff if you're a wizard, John Rhys-Davies tells you that they look like Zara from Spielburg
-Kokeeno Pookameeso is Greek for red shirt. Also the fact that he dies early in the game is meant to be a tribute to Star Trek where red-shirted people often die.

That's all I can think of

Don't forget a rather silly one.

In QFG 1 and 2, type in the command "pick nose" (but save first). This will cause you to pick your nose, and will kill you if your lockpicking is low. (With high lockpicking, you can open your nose, but is that good for anything other than practice?)

In the remakes, I believe you do this by using a lockpick on yourself.

-In the QFG2 remake, you can sometimes see King Graham dead in the desert. I don't think this was in the original game because I think the original QFG2 came out before KQ5.

It's King Arthur from Conquests of Camelot., same as the previous one.