Shopify's theme "Dawn" offers two blog layout options: "Grid" or "Collage," but this is an example of how to add a list-type layout in addition to these.
Example of settings for displaying the "List" type layout other than "Grid" or "Collage" on the blog screen of the theme "Dawn"

[(For the Dawn theme) Setup procedure ①] Add the scheme to "main-blog.liquid" and the label to "ja.schema.json"

[(For the Dawn theme) Setup procedure ②] Add code to change the layout type to "main-blog.liquid"

[(For the Dawn theme) Setup step 3] Add the code for the list layout to "section-main-blog.css"

