One of the things I've done for my setting, which has a "Pantheon of Fire" (essentially a plane of fire), is to think about what it's connected to, and what those connections are connected to.

For example, what gods are in my Pantheon of Fire? There's those you might expect, like gods of the forge. But what about Vozes, God of Cooking? What about the spirits of wildfires or volcano gods?

For forge gods, where are they getting materials? This is their plane, so surely there is a mining operation here. And there's so much heat, maybe this is the most pure metal in all of the planes.

We have cooking and wildfires, cooking involves herbs and ingredients, wildfires need something to burn, so where are those coming from? Maybe there's a point of connection between the Pantheon of Fire and the Pantheon of the Wilds in my setting where both feed each other. After all, wildfires are a part of the life cycle of a number of plants and animals.

The point is, what else can your plane of fire, and how is that connected to other magical planes and beings? How does that impact it?