Keyword spamming is absolutely taboo nowadays, but good content cannot do without keywords, because ultimately they determine, along with the appropriate secondary keywords, what your content should stand for. If you sell shoes in your online shop, "shoes" is of course also the first relevant or main keyword that belongs on your list. Other key words for this topic would then be sandals, boots, sneakers, high heels, footwear, shoelaces, buckles and so on.
Search your competitors' pages and see which keywords they are using. You should use the terms found and, if possible, add more. There are also numerous tools for research that can be downloaded from the internet, some of which are free of charge and some of which are paid. Classic synonym dictionaries can also help.