The many creatures are listed after the word creatures. Replace the period with a colon and don’t capitalize thousands.
Use italics for emphasis, not asterisks.
I’m leaving Her capitalized because it appears to be used as a proper name rather than a pronoun here.
The Swamp of Sorrows is home to many creatures: thousands of insects, hundreds of amphibians, dozens of mammals, and Her.
I do wonder if the many creatures are actually many species of creatures. Thousands doesn’t seem all that many when you’re talking about insects, because you can easily have thousands in a single gnat swarm, for example. Nor, for that matter, is hundreds a lot when you’re talking about amphibians. I’ve seen mere farm ponds that were home to hundreds of amphibians… A swamp with only hundreds of amphibians is rather pathetic, as swamps go. What if we change the numbers? The Swamp of Sorrows is home to many creatures: millions of insects, thousands of amphibians, dozens of mammals, and Her.