Prior to release, Hello Games had assured players that there were numerous easter eggs to uncover throughout No Man's Sky, and so far, just a handful have been discovered. Bellow you'll find the discoveries, with updates incoming as more easter eggs are uncovered.
The Korvax Monolith
This particular easter egg is unconfirmed by Hello Games, and overall I'm skeptical if it is actually truly in the game. Upon preliminary examination, it may seem as though it is a muddling of words, the equivalent of scrabble vomit, but truthfully it is a jumble of references written backward. The translation is: "A long time ago, in a galaxy far far away, we, the kovax (Korvax) sought to boldly go where no one had gone before. And so we each took up our towels, held our thumbs aloft and hitchhiked our way across the universe to carve a monolith." This references Star Wars, Star Trek, A Hitch Hikers Guide to the Galaxy, and 2001: A Space Odyssey. My skepticism for this particular Easter Egg is present due to the misspelling of the alien race, Korvax. If it turns out to be a legitimate find, it would be both a wonderful reference, and humorous considering the lack of attention to detail.
R2D2 Ship Variation
When exploring deep into space, you will come across more interesting and varied ships. One of the randomized additions is the robotic helper variant. This robotic helper, is of course, reminiscent of the most famous of all robotic space explorers of all time, R2D2. Though he doesn't beep or boop you to nearby points of interest, this robotic companion does offer an interesting new component, and implied moral support.