Those are all excellent!
I like the "zoom at the top" one; that's really unique. You must be using doubles?
bib is using my formula for Ultra Fractal which uses double as the default accuracy (though it does also allow arbitrary precision).
The formula he is using is here:
http://www.fractalgallery.co.uk/MMFwip3Dformula.zipI am currently working on tidying up a new updated version which includes (pseudo) ambient occlusion and modification of the DE threshold based on distance from viewpoint and image plane distance plus is more than twice as fast at rendering z^p+c for integer powers 2<=p<=31 for the "sine" versions of the triplex formula and even faster for Juliabulbs.
Edit: The updated version of my formula is now available here:
http://www.fractalgallery.co.uk/MMFwip3D.zipThere are two versions of the formula in that UFM file, the latest one is "Wip3D5".