There are 3 different types of consensus protocols:
Classical, Satoshi's, and a new one released last year called Avalanche
Emin Gün Sirer is a professor at Cornell and founder of Ava labs and he explains how each works, and the history behind them.
The newest, Avalanche, was released anonymously last year by a group calling themselves "Team Rocket" ('Team Rocket' is a reference to Satoshi's enemy in Pokemon). They created an entirely new consensus protocol, that is now being experimented with by multiple groups in the crypto space, including Emin who is developing a protocol called "Ava" (I explain Ava in my next video).