If you set up a Google account, go to their Calendar section. You can search for calendars for all sorts of events, one-off’s or a seasons worth. I added about 7 or 8 to my Google Calendar which also syncs to my Android phone. It’s a brilliant way of keeping up to to date with it.
The information is only as good as the person who constructed the calendar but so far I’ve not had any problems. I did an IndyCar one which I can share if you want?
I just go through all the motorsports I’m interested in on their Wikipedia page and add their year’s worth of races to my own Google calendar. Then I search for ones I’ve never heard of and do the same.
There is so much more amazing motorsport out there beyond Formula 1. I watched the Super GT first round from Okayama (Circuit TI Aida) during the week. 82 laps of sportscar brilliance and only 0.5 seconds in it at the end. Thrilling stuff!