I found a great tutorial over at danceypantsdisco on how to make these beautiful eggs. I was especially interested in making the blue ones. If you want to know in detail how to make everything head over to her blog. I'll just give a quick explanation on how I did it.
So what I used was red onion shells, yellow onion shells, red cabbage, beetroot, turmeric and various flowers/plants. Put each veggie/spice in a separate pot and boil it with water for about 20-30 minutes. When boiling the onion shells, use more shells than I show on the picture.
Wrap your flowers and plants tight to the egg with pantyhose fabric.
And then put the eggs in the cooled dye liquid and let it stand for about 8-10 hours. If you add vinegar to the dye it will give the egg a much stronger color. My dark blue eggs are with vinegar and the lighter blue are without. The pink-ish egg is from beetroot.