Built-in pop up flash
Built-in pop up flash is quite common for digital camera. They are handy to use. However, they may be under powered for day use. Also, they may cast shadow when shooting at close objects.
Usually, professional type DSLR does not feature built in pop up flash. This is mainly for leaving more space for a larger viewfinder prism. Do not get it wrong: DSLR without pop up flash is not necessarily a professional model. For example, Canon EOS 6D does not feature a built in pop up flash, but it is clearly an entry level DSLR in many aspect.
Regular external flash
Most DSLR and more advanced compact digital camera
Twin flash and ring flash for macro photography
Some flashes such as twin flash and ring flash were designed specifically for macro photography. However, these products are not necessarily better than regular external flash. Generally speaking,