These can take many forms, such as:

• xTokens, which represent a claim on growing pool of the underlying token that is automatically purchased with user fees.
• Liquid staking derivatives like stETH and rETH which represent a claim on growing pool of ETH from validator rewards.
• Liquidity Pool Tokens (LPTs) for AMM-based exchanges like Uniswap-v2, Balancer, and Curve, which represents claim on growing pool of user fees from swaps.
• Share tokens in money markets like Compound (cTokens) or Aave (aTokens), which represent interest bearing version of the token
• Share tokens in yield aggregators like Yearn (yTokens), which represent a share in the pool that receives the gains from the underlying strategy.