I have thunderbird with the lightning and the google calendar extension. It works almost perfect, which means that the tasks and events are imported correctly, the calendars synchronizes properly and so on. The only thing that does not get imported are the so called google reminders. Can someone help how to get them imported as well? I tested with the newest version of thunderbird provided in the repos (52.9.1) on Ubuntu 18.04 and Ubuntu 18.10.
You could use the built-in ubuntu gnome calendar program. You can log in to Google in the settings.