Here are a couple of API discovery resources I refer to often to either find something or for inspiration:
ProgrammableWeb - catalog of almost 25,000 API’s - very comprehensive, but you kind of need to wade through because their search isn’t very comprehensive (no faceted search or sorting).
RapidAPI Hub - catalog of over 10,000 API’s - with free account you can test API’s in-browser. The API’s are more curated than on PW.
Hope this helps someone!
John