Baymard Institute
Focuses primarily on e-shops. The premium section with complete recommendations is paid, but many articles are available for free, and they also send a regular newsletter featuring a portion of the recommendations from the paid section. Subscribers also get access to their own website audit tool.
Nielsen Norman Group
Covers UX in a general sense. For e-shops, the most interesting content includes the larger studies they publish from time to time. They dedicate an entire section of these studies to e-commerce.
Econsultancy
Takes a broad view of e-commerce with a stronger focus on marketing. Worth noting is their case study database, which can serve as a starting point for more specific problems.
GoodUI
Aggregates A/B tests from real websites, including e-shops. The data should be taken with a grain of salt, as it doesn't describe the methodology and context of individual experiments in detail. Suitable as inspiration or a supplementary source.
UserTesting
https://www.usertesting.com/resource-library/collections/ecommerce
Covers a broad range, so you need to dig deeper. Particularly interesting are the larger reports they publish based on their own testing. Articles tend to stay on the surface and offer more of an introductory overview than specific recommendations.
Shopify UX Blog
Active, but a large portion of content is devoted to promoting Shopify as a platform. That said, you can find specific case studies here — you just need to look for them.
UX Collective and UX Planet
Larger blogs focused on UX in general. Quality may vary, but more specific case studies can be found here too. Both sources are best suited for designers — without a solid UX background, it's hard to evaluate the quality of individual articles.
Nick Babich
A product designer who also works as an editor for the aforementioned UX Planet. He has recently shifted focus toward AI, but historically wrote a great deal about e-shops. His articles tend to be short, very specific, and generally maintain high quality.
Ondřej Ilinčev
https://www.ilincev.com/category/e-shop
Focuses on CRO in general; his articles are specific and to the point. You can take both broadly applicable principles and very concrete recommendations that come directly from his own work.
