Hello!
This is where I'm developing my personal campaign setting for Dungeons&Dragons 5th Edition. The general concept is to create scientifically sound justification for most everything in the world. Whether it's the way the landmasses form, the climates of those landmasses, how the arcane functions, or how species developed and where they're commonly found. No "There's bugbears in these woods because that's where they are," scholars would have a fairly educated guess that they arrived on the continent from a land-bridge that's disappeared, and they adapted to the pine forests in the northern part of the country.
Some interesting ideas of note that I plan to implement: