Consider the Mandelbrot and Julia formulas:
zn+1=zn2 + cm
zn+1=zn2 + cj
Where cm is changed for each pixel when calculating the Mandelbrot image and cj is constant for each pixel when calculating Julia images.
The hybrids below uses different methods to mix the two c's together in one picture.
Alternates between using cm and cj using different patterns for each iteration.
c = (1 - k) * cm + k * cj, With k = 0 at iteration 1 and k = 1 at maximum iteration.
c = (1 - k) * cm + k * cj, With k = 0.5 * sin(period * iteration) + 0.5.
Several different periods were used.
c = 0.5 * cm + 0.5 * cj