What is the Best Thing to Cover Your Tooth with After the Removal of a Gold Crown on Front Teeth?

E-MAX, could be the best option, if not any metal free crown. This will
make it look more natural and you will achieve what you are looking for and it
will be strong enough.

The best restoration for a single crown on a front tooth is an all ceramic crown made of Empress.  It still offers the best esthetic result. Your dentist may also offer an EMax crown. Your dentist should determine which will offer the best esthetics based on several factors.

If you already had gold crowns on one or more of your front teeth, and the gold crowns are being replaced, then for front teeth you will most likely want some type of tooth colored crown so that it will look like a real tooth again.

The most "real looking" and natural will be an all-porcelain crown with no metal underneath.  My favorite right now is the EMax porcelain material.

Another alternative type of tooth colored crown is porcelain fused to metal (often called a PFM crown).  These have been used in dentistry for decades and are the standard treatment used by most dentists.  However, because of the metal underneath the porcelain, these crowns don't look a natural as all ceramic (with no metal underneath) crowns.  This is because light doesn't go through and disperse through the PFM crowns, whereas they do with all porcelain crowns.  Generally the fee for all porcelain crowns are a bit higher than PFM crowns because it requires a little more time to place, and also the lab bill is usually higher as well.

You might want to refer to the cosmetic dentistry blog link below that has articles that show examples and discuss the differences between PFM crowns and all porcelain crowns.