Flax seed makes for a good egg substitute so long as that you are using it to bake goods that isn’t yeast based. For one standard egg, take your flaxseed meal and combine with water, leaving it to set for 10-15 minutes before using.
Flaxseeds also goes by the name linseed. If flaxseed meal is not available at your store, try looking for linseed and make your own flaxseed/linseed meal at home. Simply by putting some in a spice grinder and blitzing until the texture is mealy. Do remember that flaxseed meal oxidates and turns rancid fairly quick, so I suggest making a little at a time and storing it in an air-tight container.
1 tbsp ground flaxseed meal
2 tbsp water
In a small bowl, take 1 tablespoon ground flaxseed meal and add 2 tablespoons of water. Leave it to set for about 10-15 minutes until the consistency is gelatinous.