No fiction for the Wilderlands that I'm aware of offhand. I may try to wade back through my Dungeoneer/Judges Guild Journal/Dungeoneer Journal/Pegasus/whatever magazines to see if there is any short fiction set in the Wilderlands there. I think that would be our best bet.

And I just don't know enough about Mystara to really know which eras were BM eras or not. I have copies of the gazeteers but never really read them much. I bought them because they were cool, and keep them because they are cool, but I don't really play that edition of D&D much so I don't often think to dust them off and read them.

Which Gazeteers (if any) have any actual details about the Mystara version Blackmoor?

In that vein, it's so easy to create a link between WL's Dragonkings, the Dragonfather, and the Dragonlords.

But I don't have my materials on me, so that I'll leave for you to research...