The definition of "top" varies greatly person to person or even in the context it is used in.
Monero has been up and until now the king, so it's their crown to lose.
If we are talking biggest gainer, I don't think there is any doubt that DeepOnion will breakthrough, particularly after the airdrop has concluded and has been listed on a big exchange.
If the question is regarding technology or anonymity, most from the list provide it, but in different ways and at this stage it is difficult to have a definitive answer, especially as they are constantly progressing further into greater anonymity.