Polkadot is going completely parabolic the last few days/weeks and the potential is huge to invest in the Ecosystem coins arround this technology.
I believe that coins like ChainX (https://coinmarketcap.com/currencies/chainx/) and Kulupu (https://coinmarketcap.com/currencies/kulupu/) are the hidden gems at the moment.

The market cap is low and the potential is huge.

Chainx (PCX)will make a bridge between Bitcoin and Polkadot. It transforms Inter-chain assets in a standard way. Any chain can have asset interoperability with all other chains as lçong as it establishes a connection with chainX.

Kupulu (KLP): Kulupu is a self-updating self-governed blockchain system, using proof-of-work as its consensus engine. Kulupu is built with the Substarte framework. It is one of the first blockchains that combine proof-of-work consensus engine with forkless upgrades.

The market caps are still very low but the potential is truly huge.
These projects are going to skyrocket in the next few days/weeks.

Hope this info is useful. Please always do your own research and this is not investment advise.