Companies that began life as mail-order catalogs still offer you a chance to get on their mailing list. And so do some retail stores who have sent out catalogs for years. And a few companies put the equivalent of a paper catalog up on their site, so you can download it and read or print it using Adobe Acrobat or Microsoft Word. The lists should help you find a product by category when you don't have a particular product name, brand, or phrase to enter in a search box. These lists resemble a table of contents in a book, where you turn to a chapter that seems to cover what you want, then look at the headings to find one that seems most relevant.
Searches are more like using the index.
Most sites offer a list of product categories on the welcome page. When you spot a subcategory you like, you click that and get, perhaps, a list of brands. You are drilling down, down, down into the store's inventory. This hierarchy may be well designed or not. Bad designs force you to click, click, click, going down as many as ten levels to get to a particular product.