$ETH

1. *Trading pairs*: ETH/BTC, ETH/USDT, or ETH/USD can be used for trading and investment strategies.

2. *DeFi pairs*: ETH/DAI, ETH/USDC, or ETH/LINK are used in decentralized finance (DeFi) applications, such as lending, borrowing, or yield farming.

3. *Productivity-focused projects*: Ethereum-based projects like Gitcoin, Radicle, or Cent can enhance productivity in areas like open-source development, collaboration, or content creation.

Which specific productivity aspect are you interested in? I'd be happy to provide more tailored information.