Hashgraph is a gossip-protocol consensus developed by Leemon Baird. Nodes share their known transactions with other nodes at random so eventually, all the transactions are gossiped around to all of the nodes. Hashgraph is really fast (250,000+ transactions per second) but isn’t resistant to Sybil attacks.
So Hashgraph is a great option for private networks, but you’re not going to see it implemented in a public network like Ethereum or Dispatch anytime soon.
"The Swirlds hashgraph consensus algorithm is explained through a series of examples on a hashgraph. Each page shows the hashgraph with annotations explaining a step of the algorithm. This covers the core algorithm, from creating transactions, through finding their consensus order and timestamps." see http://www.swirlds.com/downloads/SWIRLDS-TR-2016-02.pdf