D&D 5E Standalone obscure monsters vs enriching races

[Casimir Liber]

By this I mean (for instance) treating derro as a deranged aberrant sub-people of dwarves, and redcaps as a bloodthirsty cult of gnomes. Broadens scope of race with diverse sub-populations and give some otherwise isolated monsters a place to integrate with broader monsters.......

 

[Lyxen]

Why not, but I'm happy as well with specific races being spawned by obscure gods and heroes of forgotten places, D&D is not a place for complete logic and anthropomorphism, considering all the various planes, their influences, the powers there, etc.

 

[Tallifer]

I like both approaches: the former speaks to my love for Tolkienian worldbuilding and Piers Anthony weird biology; while the latter has the imaginative excitement of Frank Baum and Edgar Rice Burroughs.