Polkadot (DOT) ?

Polkadot, like many post-Bitcoin cryptocurrencies, is both a token that can be bought or sold via exchanges like Coinbase and a decentralized protocol.
The Polkadot protocol is designed to allow unrelated blockchains to securely talk to each other, so that value or data can flow between, say, the Etherium and Bitcoin blockchains without any intermediary. It’s also designed to be speedy and scalable, via the use of many parallel blockchains (or “parachains”) that take much of the processing demand off of the main blockchain.   
Gavin Wood, a co-founder of Ethereum, came up with the idea for Polkadot and released its white paper in 2016. The next year, Wood and Peter Czaban founded a nonprofit organization, the Web3 Foundation, dedicated to the development of Polkadot. Robert Habermeier, who has a research and development background in blockchains, is also a co-founder of Polkadot.
Polkadot has two types of blockchains:

• Relay chain: This is the central chain of Polkadot where transactions are processed. It's designed with minimal functionality because its purpose is to manage the system as a whole.
• Parachains: These are parallel blockchains that run on the Polkadot framework and can communicate with each other. Each parachain is its own blockchain and can be designed toward its specific use case.

Polkadot is an intriguing investment opportunity because it's only scratching the surface of its potential. It launched its biggest innovation, parachains, in December 2021, and it's gradually adding parachain slots.
Because Polkadot is such a popular cryptocurrency, it's easy to buy. There are several top crypto exchanges that offer it.