I don't have a consistent style for everything and it depends on the circumstances. snake_case is often used, especially to avoid spaces. Sometimes I just do flatcase instead, and in rare cases also kebab-case or combined_snake-and-kebab-case. The combined_case is often useful to group parts of the name, like a dates and version numbers together and to indicate what part is constant; example-name_2024-08. Sometimes I also do the "Title Case", which is basically PascalCase, but with spaces. Or even even more weird, "Python_Case", which is PascalCase, but with snake_case, when I want to avoid spaces.

I often avoid dots in regular filenames, unless they indicate a file extension or format, such as ".svg" and ".inkscape.svg" to indicate its a specific version of the SVG format. Or ".xiso.iso", as a specific compressed version of the regular ISO file (for use with Xemu emulator). Basically the same logic and tradition as ".tar.gz" (but in reverse order).