Here is an egg with realistic wood grain texture to add to the eggs designed by Antonin_Nosek. This model is the same size as them and could be printed in wood PLA.

On my older Ender 3, I used a 0.6 mm nozzle to prevent clogging with a wood-filled PLA.

Used Fusion 360 to design a basic egg shape that is the same size as the source eggs. Then I took the file to Blender to apply a displacement map of wood grain to the outside of the egg.