If you’re willing to go even further into homebrew, how about a Latin/Germanic divide?

Medieval Europe can be VERY roughly thought of as having a “Latin” South and a Scandinavian-Germanic North. D&D’s fantasy aesthetic draws in a large part from the Latin Matters of France and England (courtly tales of knights, monsters and enchanters) while the races of elves and dwarves are more from the North (where Tolkien derived them).

It would be neat if a similar divide was represented in your world. Sail the Northern coasts and you will meet elves and dwarves galore. Head down into French and Italian territory though, and you start running into the creatures they believed in. Skiapod’s race alongside cavalry while Panotti merchants wrap their ears around their bodies like cloaks. Everywhere are wonders straight out of Pliny.

If interested, I highly recommend the book “Baudolino” for more ideas on creatures and medieval legends.