A 64 bit version of the fractal flame editor Apophysis. There are options to use multiple processors.
The original Apophysis is a windows application made in Delphi for creating, editing and rendering fractal flames.
Fractron 9000 is a high performance fractal flame renderer for Windows.
Fracture is a screensaver for OS X that creates a wide variety of fractal images.
Fraqtive is an open source generator of the Mandelbrot family fractals.