Tube amps known to have a low damping factor?

Which tubes amps are known to have a characteristically low damping factor, 20 or less? Which are known to have a characteristically high damping factor?
CAT JL-2 has a DF of 10. Why do you want a low DF? I thought I high DF was desireable...
Higher damping factors are not a free lunch; something has to be traded off to get there, and that something is the ear-friendly distortion behavior of a low (or zero) global negative feedback amp.

Most SET and OTL amps have a low damping factor, but they work fine on speakers designed with such amps in mind.

I suggest reading this paper before you select an amplifier; it will be helpful regardless of what type of amp you go with:

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I appreciate that people are willing to share their expertise... but I'm just hoping that someone will be generous enough to share the fruits of their labors so I don't have to do the work myself. A list for the rough parameters indicated is all I'm looking for.