i think polkadot might have a chance and that is the only one right now. will see and it is going to be really fun to watch if it do happen, the altcoins war pump again.
i am also with this one, Polkadot has a chance, but it is a long way for them to go to overtake Ethereum on position two, there is Chainlink as well, but i do not think that LINK could overtake Ethereum while sits on Ethereum, they would have to launch their main-net before or took a part on other chains as well