I’m starting this post as an ongoing research and bucket of knowledge, which will be updated and modified to make it more structured and comprehensive.

For this specific piece, we are taking Shopify as our starting point.

Let’s start with the problem:Online stores must stand out and delight customers with cool-looking custom-crafted experiences and landing pages.

What does Shopify as a platform itself offer merchants?

Shopify Admin: Not much up until now; after releasing of the OS2, there are more options in the theme editor and more on the CMS vertical to come soon.We will focus on this topic separately.
Apps and extensions: Main Shopify Philosophy is — There is an app for that; they're crafting a base where each merchant can quickly start their operations but intentionally are taking a long while to consider what next should be implemented into its core, letting their extensive community of apps developers earn a bit.The two most prominent players in this space are Shogun and PageFly.We’ll talk soon about problems caused by using too many front-end-facing apps.
Custom code within Theme, implementing designs then HTML and then Liquid using either built-in Shopify Theme Code Editor or connecting it properly via Git repository
Headless Storefront hosted on CDN custom-coded fine-tuned high-performance custom customer experiences (hope I used all positive buzzwords)
3rd party Page Builders — tools that allow a specific level of magic and different approach.

What do other platforms offer to merchants?

The good news is that we can approach the topic from the other side, the CMS side.

Strapi allows pulling Shopify data through the plugin
Storyblok offers PageBuilder experience inside of it and, as a headless CMS, allows pulling data from anywhere (cross-platform) and Shopify.
WordPress — use Elementor/Divi or any other page builder while pulling data from Shopify and treat it as a buy button.
I can imagine Contentful, Sanity, and many other headless CMS’es are considering eCommerce as an attractive vector and have some enablement too. I hope we will explore it in other posts.

TLDR; Here is the list in no particular order(please add more in the comments)

https://www.replo.app — headless page builder
https://www.shopyflow.com/ — headless page builder
https://shopstory.app — headless page builder
https://wpshop.io/ — stitch Shopify data to WordPress and master pages in WordPress
https://readymag.com — generate Buy button inside Shopify and use Readymag as a standalone Pagebuilder and hosting similar to WordPress approach above
Udesly.com
Please add more in the comments!

PageBuilders I’m skipping for now but are cool too:

https://www.ycode.com/
Webflow
EditorX
Builder.io
Shogun Frontend
https://www.ceros.com/editor/ — nice because allows to hold content to the brand guidelines
Webwave.me
https://www.automizely.com/page-builder
https://www.paperflite.com/
https://www.foleon.com/create/landing-pages
https://www.webiny.com/enterprise-serverless-cms/page-builder — nice because it’s Open-source, headless and serverless :)
https://nyla.app/
https://www.stackbit.com/
https://showit.com/
https://breakdance.com/
https://storipress.com/
https://vercel.com/blog/visual-editing
https://ecomposer.io/
https://livecanvas.com/

PageBuilders as a multi-platform listings injectors

yeah you heard it right, a whole tool that focusing to create a product details page and then publish it everywhere :)

Replo.app

From 0 to 499, Unlimited PageViews but a limited amount of Pages: 100 pages for $499 a month.

UX/UI of a PageBuilder

,Error: [31m The Parser function of type "raw" is not defined. Define your custom parser functions as: [34mhttps://github.com/pavittarx/editorjs-html#extend-for-custom-blocks [0m,

Shopyflow.com

Using Webflow as an editor, Early stage gathering interest, not much more info at the moment

Shopstory.app

No pricing requires coding, works with Contentful, and for coders, docs and tutorials with NextJS are available.

UX/UI of a PageBuilder

,Error: [31m The Parser function of type "raw" is not defined. Define your custom parser functions as: [34mhttps://github.com/pavittarx/editorjs-html#extend-for-custom-blocks [0m,

Wpshop.io

Use Elementor as a page builder and pull data from Shopify to render buy buttons.

$199 annually for 1–3 sites, or $499 annually for an agency plan that gives unlimited sites

Udesly.com

Price: 0 or 99 EUR annually

Readymag.com

Price: $0 — $60 with $36 is packed-up with features enough.

It is a standalone page builder like Wix, Webflow or Weebly that allows to implement integration with Shopify through injecting their Buy Button into the template of a page created inside Readymag tutorial below:https://help.readymag.com/hc/en-us/articles/7008544525723

Disclaimer:

Obviously, I chose Shopify not because it’s the best eCommerce platform but because it’s one of the most popular platforms currently (not the best, but very good and therefore popular)

The popularity of Shopify chokes the share for 3rd party apps to be present on other platforms, a limited amount of $$$ requires them to make a choice and therefore makes it also a #1 priority platform to release the integration with or to release the whole experience there first or exclusively there, and there are many examples of such behavior.