Google released a search trends dataset earlier this month. Using this dataset, Adam Pearce made an explorer to compare search volume over time:
The COVID-19 Search Trends symptoms dataset shows aggregated, anonymized trends in Google searches for more than 400 health symptoms, signs, and conditions, such as cough, fever and difficulty breathing. The dataset provides a time series for each region showing the relative volume of searches for each symptom.
Even if you’re not keen on analyzing Covid-19 data, this is likely a good time series source to at least bookmark for later.