Blogger paragraph types are Normal, Heading, Subheading, and Minor Heading. How can I add a Code type that will set a small, bold, fixed-width font?
You can add a Code style to your template (Template / Customize / Advanced / CSS).
But you cannot add the value to the drop-down menu in the post editor's Compose mode. Instead, to use the style you need to switch to HTML mode, and apply it manually with something like
<div class="yourClassName"> your paragraph of code </div>