Outside of those two (now 3), I thought also there were a bunch of relatively harmless coronaviruses that people just consider comparable to common cold.

Wikipedia says:

Coronaviruses were discovered in the 1960s.[8] The earliest ones discovered were infectious bronchitis virus in chickens and two viruses from the nasal cavities of human patients with the common cold that were subsequently named human coronavirus 229E and human coronavirus OC43.[9]

https://en.wikipedia.org/wiki/Coronavirus#Discovery

And later:

Coronaviruses are believed to cause a significant proportion of all common colds in adults and children.

The coronaviruses HCoV-229E, -NL63, -OC43, and -HKU1 continually circulate in the human population and cause respiratory infections in adults and children world-wide.