Cardano fans should take a quick peek at the Plutus and Marlowe testnet documentation and playgrounds. Even if you don’t understand it, the quality of the documentation they added is remarkable.
The Plutus sample code and playground is really cool (examples for games, crowdfunding, messaging apps, etc).
Next up is Marlowe, and the Meadow engine. Basically a prefab node based drag and drop system. I don’t think anyone else in crypto has a system this advanced or user friendly.