1. Symmetrical fold mountains: These are mountains that have a regular, symmetrical shape, with a steep front and a gentle back slope. The Himalayas are an example of symmetrical fold mountains.

2. Asymmetrical fold mountains: These are mountains that have an irregular, asymmetrical shape, with a steep front and a long, gentle back slope. The Jura Mountains in Europe are an example of asymmetrical fold mountains.

3. Overturned fold mountains: These are mountains that have been overturned, so that the original front slope is now the back slope and vice versa. The Alps are an example of overturned fold mountains.