The Unitroller contract has an array called allMarkets that contains the addresses of each fToken contract. Each address in the allMarkets array can be used to fetch a metadata struct in the Unitroller’s markets constant.
Unitroller
fToken[] public allMarkets;
Solidity
Unitroller troll = Unitroller(0xABCD...);
fToken fTokens[] = troll.allMarkets();
Web3 1.0
const unitroller = new web3.eth.Contract(unitrollerAbi, unitrollerAddress);