[set fair (OP)]

That is do we know which specific cold viruses were around during late last year and early 2020 and how many people were infected?

There was a report in the Times that prior infection with a cold causing coronavirus may confer some immunity https://www.thetimes.co.uk/article/coronavirus-having-a-common-cold-can-help-to-fight-virus-nhp73dcd0 I haven't managed to track down the study/article in the Journal Cell so I don't know if the Times piece was accurate or not.

[Bored chemist]

do we know which specific cold viruses were around during late last year and early 2020 and how many people were infected?

Do you report it to anyone if you get a cold?

[set fair (OP)]

Ever thought of changing your name to  Boring Chemist?

[Bored chemist]

Ever thought of asking sensible questions?
You already knew the answer to your first question here. Were you too lazy to think about it, or not bright enough?

[Petrochemicals]

I dont know whether this is any help.

https://www.dailymail.co.uk/news/article-2804670/80-people-die-Britain-DAY-flu-pneumonia-Europe.html

[alancalverd]

It's a pity that the Common Cold Research Unit was closed just as the techniques of analytical virology were accelerating.

[Colin2B]

I haven't managed to track down the study/article in the Journal Cell so I don't know if the Times piece was accurate or not.

This might be what you are looking for
https://www.cell.com/action/consumeSharedSessionAction?JSESSIONID=aaa1NJyCFwb-N_ZWNvAjx&MAID=xLI9LK9cNfTx7ifepyVX0w%3D%3D&SERVER=WZ6myaEXBLHNN%2BUWpfIEYQ%3D%3D&ORIGIN=517237819&RD=RD

As @Bored chemist said, people don’t report common cold infections and @alancalverd points out research into common cold virus was suspended.
It looks as though exposure to some cold viruses might trigger an immune response that might confer some degree of reduction of Sars2 effect.