ABI Ninja lets you interact with any contract on Ethereum:

• Verified contracts (pulls the code from the Etherscan API)
• Unverified contracts (providing the ABI)

It includes nice features like: (mainnet!) ENS resolution on address inputs, shareable URLs, navigation, show TX results, etc.

Live version: https://abi.ninja (GH: https://github.com/carletex/abi.ninja)

Currently working on UI/UX improvements: https://stage.abi.ninja/