card.io might be a bit more popular than Iceberg Editor. We know about 1 link to it since March 2021 and only 1 link to Iceberg Editor. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Regarding the backend editor, there's a plugin called Iceberg that do just what you described: https://useiceberg.com/. Source: over 2 years ago
First thing I tried was typed card.io in my web-browser to see whether it would bring me to a website associated with this game. Source: over 1 year ago
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