I am currently searching for DBZ type white dwarf.
I've been looking into rare White Dwarfs (or Dwarves, both seem correct) for the last few months. As is the case so often (and has already been pointed out) EDAstro ist the place to check first to get some initial directions as to where things are to be found in general:
That square N/W of Sgr*A? That's the stack of sectors I've been working on. According to EDD I'm the proud discoverer of the following rarer White Dwarfs, most of which I've found there:
- DAZ: 110 out of 705 (Spansh) or 971 (EDSM)
- DBV: 54 out of 1656 (Spansh) or 2062 (EDSM)
- DBZ: 24 out of 207 (Spansh) or 257 (EDSM)
Besides the visualisation of all White Dwarfs EDAstro also provides a
CSV listing these rare types, i.e. DAZ, DBV and DBZ (excluding the hand-authored DQ-variant). A quick plot of its entries in Excel shows they're pretty much distributed in the same way as all other types of White Dwarfs:
To answer your question based on my observations: The easiest way to find an undiscovered, rare type of White Dwarf is the same as with HRGG: Search for one close to you (on EDSM or Spansh) and then scan through the boxel via the Galaxy Map's search function. Chances are good you'll find another one of that type within that boxel.
Other than that my survey so far has not turned up any discernable patterns as to where they're generated. Good luck!