With the DOT hype my pick is
DARKSub ~1million marketcap
6.5 million circulating / 10 million max
18% cold staking via wallet
decent tokenomics and good development happening
I just posted a topic here for more info
https://bitcointalk.org/index.php?topic=5315181.0SHIFT NRG also seems to be moving to DOT but I haven't enough research yet - look into it though if you're keen

NRG is moving to DOT too?

This is a bad news for Ethereum, it seems that many projects are moving into Polkadot and more will leave in future, the only thing dragging Ethereum down right now is high gas fee and I don't think vitalik can do anything about this right now, the best altcoin I'm holding for possible insane surge soon are Polkadot and Avalanche