Any trusted on-chain value can be linked to a pool you create, including:
All Chainlink oracles can be added
Uniswap V2 compatible or V3 TWAP
Any other trusted on-chain value
Most Chainlink oracles already implement the functions required for the IOracle interface so they can be added directly to a pool.
UniV2 compatible pairs or UniV3 can have a time weighted average price used as the oracle. This is useful for assets which are on chain and don't have a Chainlink oracle created for them.
Any trusted on chain value can be wrapped in the IOracle interface and added to a pool for options to be sold against it.