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I imagine the goblyns from Ravenloft (why not other name?) as a mixture of living constructs and faes, and when they die collapse or desintegrate as a sand castle in the beach, or vampires being killed by Blade in the movies. Why? To can be used as monsters in a no-mature videogame, something like the husks from Fortnite: Save the World or Chinese videogames where enemies are like alien animated statues, or the giddy goons, the minions from the old 80's Dragon's Lair. Do you know David Cronenberg's "the Brood" or 1987 Carpenter's "The Children"?
Some day Birthright will come back, because it is the perfect setting for a future strategy videogame or wargame of mass battles. But not in this phase yet. Neither Savage Coast/Red Steel, but this has got possibilities, with pirates, mutants and maybe also superpowers.
I can't guess what to do with Mystara, but Hasbro could agree a lincenced adaptation with some videogame studio, for example Capcom, the creators of the D&D arcade.
If Hasbro's franchises being adapted by Renegade Studios have got a good sales level I guess the option of a Gamma World new edition would be possible.
* RL monsters? I guess it means monsters based in literature, mythology and folklore from Real-Life, but these are public domain Shouldn't these to be in the SRD with the other creatures from the monster manual?