There are many types of PCB (Printed Circuit Board) depending on the design and structure. Some common types include:

1. Single-layer PCB: This PCB has only one layer of copper on a non-conductive substrate.
2. Double layer PCB: This type of PCB has two copper layers separated by a non-conductive substrate.
3. Multilayer PCB: This PCB has multiple layers of copper and non-conductive substrates, which are laminated together.
4. Rigid PCB: This type of board is made of rigid materials such as FR4 and cannot be bent.
5. Flexible PCBs: These PCBs are made of flexible materials that can be bent or twisted along their length.
6. Rigid-Flex PCB: This is a combination of Rigid and Flex PCB that allows components to be placed on both Rigid and Flex parts.
7. High-frequency PCBs: These boards are designed to operate at very high frequencies, which makes them suitable for radio communications and other high-speed applications.
8. Metal core PCB: This type of PCB has a metal core, which helps to dissipate heat and improve thermal management in high-power electronic applications.
9. HDI PCB: This stands for High Density Interconnect PCB, designed to have smaller and denser components, resulting in more compact and efficient electronics.

These are just a few examples of the various types of PCBs available. The type of PCB used for a particular application will depend on factors such as the complexity required, size and intended use of the electronic device.