My two latest inventions are Node Faker, which simulates bitcoin-cli and bitcoind in the browser (via javascript), and Wild Explorer, which is a block explorer that talks to Node Faker to get its blockchain data
https://www.youtube.com/watch?v=QAc4L7tSZMs
For more info, see their respective githubs:
Node Faker: https://github.com/supertestnet/node_faker
Wild Explorer: https://github.com/supertestnet/wild_explorer