[kbs666]

Even if a creature only appeared in specific geographic locations I'd still just give it a mechanics article and make sure to specifically say where it lives in the article, assuming those places are already topics it will get linked, or give the creature a belongs within relationship to that location or both.

For items, in my fantasy realms two kinds items get topics articles. Artifacts, big, powerful MacGuffins major story arcs will be about that a lot of lore will exist for and more frequently items important to a story that I want a specific image for. I use mechanics articles any time I simply want to create a new magic item that isn't surrounded by a lot of lore and won't be central to the plot.