About how many spreadsheets are stored in your Google Drive?
Find how many Google Spreadsheets I have?
(less important) get the list of these spreadsheets?
The Sheets interface theoretically shows all of them, but in the form of infinite scroll, and without a counter.
The following script will give you the count in the Logger log. 776 in my case. Which was interesting to know.
This script will list all the names. You could write the data to a spreadsheet as well if you're looking for an index of sorts.
How do I search for keywords in Google Docs, and see the results with context?
How to keep small images on Google Drive from counting against my storage limit?
How do I search Google Docs by filename (or better, pattern matching filename)?
How to move docs using drag and drop from the search results in Google Drive?
How to search Google Drive for Docs and Sheets?
How do I search a sub-string within a range in Google SpreadSheets?