There are plenty of different buses, these six are the most common ones and I knew none of them before I started embedded development to build my own electric cars.

CAN-Bus is the most common one today, Automotive Ethernet is rising fast due to more and more sensors and higher bandwidth applications (ADAS, Sensor networks) but the old ones are still around: UART & SPI, then finally the one-wire LIN bus for turning pumps on and off.

I hope this helps someone as a starting point.