It all depends how you define interoperable... For example splinterlands is a pretty big force in the hive blockchain as many of the in game actions require hive and they have it to where you can port items over from splinterlands and tokenize it to become an nft on wax.

As you can see projects like Gmfrens is also on wax and its a sort of cross blockchain community as well as I recall seeing chronoverse on wax as well. If any other questions feel free to ask.