Everything about "pox leber" as a minced oath, and an earlier source.

[Bluetoes101]

I wonder if we can find other words people used other than "pox", if we could then finding examples would probably become exponentially easier

In the Fastnachtspiele, the more common spelling used it "potz" (which is also closer to the original "Gotts").

Not sure if you have seen this, but looks like there are plenty of (other context) examples if you include the "p/b" variation too. They are 16C examples, but a lot of them. 

(Translated with chrome, may not be entirely accurate)
"botz,

papae, today spelled potz , an exclamation never appearing alone, always followed by a noun, which could seemingly be derived from botz = bosz, blow, as for example Fischart tonnerbotz for thunderclap Garg. 219ᵇ. 270ᵇ (You are not allowed to view links. Register or Login to view. 206) sets botz for bosse , and thunder! itself forms an exclamation. However, it is more correct to take botz, like bocks and box ( p. 202, 203) , as a euphemism or parody of Godkotz also applies. In some formulas, all these words are exchanged, e.g., in potz tausend and kotz tausend, botz blut and kotz blut, in bocks marter and botz marter, bocks leber and botz leber;schende, blende, often associated with bocks , is also found after botz. The following list of the most common formulas can be supplemented in many ways from books of the 16th century."

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