I guess this has been discussed to some small degree within online RPG circles, but I was unaware of it and think it's worth noting again. Apparently Blackmoor is a location on She-Ra's world of Etheria. Just listen to Bow in this clip...
It even plays an important role in this episode ('The Red Knight').
Now, I know the name "Blackmoor" has a sort of general fantasy feel, such that it could have been arrived at independently by the writers on Princess of Power, but the science fantasy pieces of Dave Arneson's classic setting really do make it a perfect bit of D&D lore to be "honored" in such a way.
I think that's pretty darn cool.