Hot pot as in a shabu shabu? There really are that many variations. It's all about customizing it to your tastes. But if you like Little Sheep, they sell soup base packets you can get at an Asian store. If you are really intent on making your own, the usual suspects are all from the Chinese pantheon, so stuff like aniseed/Star Anise, fennel, cloves, Szechuan peppercorn can be ground after toasting. I also use Doubanjiang, a chili paste, but I don't know what's accessible to you. Dried shiitake mushrooms add color and flavor, but if you don't like mushrooms, omit them. Saute aromatics in peanut oil as well for more flavor. And chilis to taste. The chilis interact with the Szechuan peppercorn, that's where the "mala" numbing flavor is.
Or are you asking about serving it? I use a tabletop induction stovetop to keep it simmering. You could use a sterno I guess. Or if it's just you, just keep it on the stovetop and come back to it when you need more broth.