There are several different types of stock, here are a few of them I use.
*Simple stock- combine flavoring ingredients with water and simmer for a specific amount of time (cooking times may very according to the type of stock your making). Chicken stock, vegetable stock and fish stock are examples of simple stocks. They are normally used to prepare soups, grains and vegetables. Skim often.
*White stock- a neutral flavored stock made by blanching the bones in water before marrying them with water, vegetables and herbs. The most common whites stocks are made from beef or veal. White stocks are great for adding body to certain dishes without changing the flavor much.
*Seafood stock- made from shrimp and lobster shells, some fish heads or bones. The remainder of the ingredients may include different types of vegetables, herbs and cold water.
*Brown stock- cook on stove top or roast bones and vegetables until deep in color before adding cold water and aromatics. For more flavor and color you may add tomato paste to the bones before roasting and/or you may add a oignon brûlé (burnt onion) for additional flavor and color.
*Fumet- a white stock typically made of lean, white flat fish bones, such as flounder or sole. Cooked gently with vegetable aromatics typically a white mirepoix (onions, celery, parsnips, leeks and mushrooms). For added flavor you may also add a small amount of white wine after the vegetables have been cooked. Cover the pot in order to capture as much flavor as possible, creating a liquid that is not normally as clear as other stocks.