Styles are not something you are likely to want to download (and they'd have to be in some sort of InDesign document or template to load them).
Do you understand waht styles are and how they are used in your documents? Have you read the Help files on using styles and on making a TOC?
The entries in the TOC are made from the text of paragraphs in the body of your work that have the styles applied that you selected. You ahve the choice of assigning the same style to the entries, or of creating new styles to use, just as you can style textr anywhere else in your document.
For example, you might have headings you wish to 8nclude inthe TOC, and they have style Headings1 applied. You can create a new style, perhaps TOC listings, to apply to the text in the TOC itself.