1. A character from Thor Ragnarok was shown in the post credit,the girl with long hair is called Hela.  2.There was easter egg in the movie which is the being that with stan lee cameo .it called The Watchers.   4.The introduction of Celestial is significant in MCU since Celestial is a part of major char in Infinity Gauntlet(Comic book,not sure how MCU going to do their own version ).  5. The 4th post credit show the gold people said the creation of Adam which is Adam Warlock who going to be major character in Infinity War.( in Infinity Gauntlet comic book series,Adam Warlock is the person who gather all marvel superhero to fight Thanos and the person who kept the Infinity Gauntlet)

Thats pretty much easter egg i found in the movie

I agreed it is not a great movie for stand alone,but it play majors part in MCU especially for the upcoming Marvel Infinity War movie