To answer the question: I don’t know yet.
So far…
Mercurial, which is an excellent sculpting tool. Can be very clean. Great with other drives and fuzzes.
Crackle Jack, small and powerful. Can fit in enclosures easily with other pcbs. Fun to stack. Even with another boost. Or another crackle jack. Fo sho’
Chickenhead. Not clean. Gets close to fuzz. Also small. You can move the bias trimpot to the outside of the enclosure.
Amentum. I’ve only used it a few times. Very clean. Small.
Both the Amentum and Cracklejack can lower the volume of the previous pedal, if you want. Which can be useful. If you crank a fuzz into the Amentum, with its volume down a bit, you can get some different fuzz tones.
Good luck. Boosts are simple. And fun.